The O'Cassidys belong to Fermanagh; this, and the borders of adjacent
counties, is their principal homeland today and it is there their sept
originated. It provided hereditary physicians to the great Maguire sept
and numerous O'Cassidys are recorded as ollavs and physicians to the
Maguires between 1300 and 1600 A.D.
The name first appears in the field of literature in the person of
Giolla Mochuda O'Cassidy (died 1143), whose Gaelic poetry is still
One of the O'Cassidys, Rory, Archdeacon of Clogher, is said to have
assisted Cathal Maguire in the compilation of the fifteenth century
"Annals of Ulster". Equally deserving of literary renown is Thomas Cassidy
(fl. 1740), expelled Augustinian friar and subsequently soldier of
fortune and itinerant, whose racy autobiography has been likened to the work
of Rabelais. He and others of the sept were sometimes called MacCassidy
as well as O'Cassidy.
After the plantation of Ulster in the early seventeenth century the
O'Cassidys, like nearly all the leading Gaelic septs of that province,
sank into obscurity. We find them only in such records as the presentments
relating to priests under the Penal Code, chiefly in counties Fermanagh
and Monaghan. Many, of course, emigrated: the grandson of one of these
was William Cassidy (1815-1873), Catholic politician in the United
States and lifelong enemy of Great Britain.
Born in 1924 in Sydney, Australia, Cardinal Edward Cassidy had a career
described as "brilliant." Ordained at St. Mary's Cathedral in Sydney in
1949, by the early 1950's Cardinal Cassidy was sent to Rome to study
Cannon Law at the Lateran University, and was never to return to
Australia for any extended period. Instead, Cardinal Cassidy joined the
Vatican's diplomatic corps. His postings included stays in India, Ireland
(from 1962-1967), El Salvador, Argentina, Taiwan, Bangladesh, Burma, South
Africa and The Hague in the Netherlands.
In the 1990's through 2001, Cardinal Edward Cassidy served as president
of the Pontifical Council for the Promotion of Christian Unity. He was
also president of the Commission for Religious Relations with the Jews.
Cardinal Cassidy is one of only two Australian cardinals -- "Two is
plenty," he has observed -- within the Roman Catholic Church.
Discussing his lifetime living abroad, Cardinal Cassidy observed, "When
you're in a country for a few months, you feel that you could write a
book about the place. After a year, you think you might be able to write
an article. After a few years, you realize that you could never
understand the place."
Cardinal Cassidy's career at the Vatican was not without its
challenges. In 1988, he returned to Rome and was named Sostituto or Substitute
Secretary of State, making Cardinal Cassidy the third highest ranking
prelate in the church, a post he held for just one year before his
appointment to his present positions. The sostituto post is traditionally held
by an Italian. The position generally controls much of what the pope
sees. As noted by one reporter, Cardinal Cassidy's genial but
blunt-spoken manner and his penchant for telling it like it is was found
unacceptable in the Vatican's world of subtlety and indirection.
Among his activities over the previous few years, Cardinal Cassidy
formally signed in June 1999 an accord on behalf of the Vatican with the
Lutheran World Federation closing the 500 year old gap between the two
faiths on their beliefs on the means of obtaining salvation. The same
month, he served as the Pope's special envoy and principal celebrant for
the funeral mass of the Cardinal Basil Hume, the former leader of Roman
Catholics in the United Kingdom, whose funeral was attended by over 500
clergy, Prime Minister Tony Blair and Irish Premier Bertie Ahern.
Cardinal Cassidy was also active on the Church's Jubilee Year 2000. He
spoke during the Pope's Day of Pardon Mass on March 12, 2000 at St.
Peter's Bascilica in Rome, where he confessed the sins by Catholics
against the Jews: "Let us pray that, in recalling the sufferings endured by
the people of Israel throughout history, Christians will acknowledge the
sins committed by not a few of their number against the people of the
Covenant and the blessings, and in this way will purify their hearts."
Born in 1937 in Lincolnshire, England, Sheila Cassidy is the daughter
of Air Vice Marshall John Reginald Cassidy, who played a central role in
Great Britain's telecommunications industry during World War II. At the
age of 10, the family moved to Australia and lived on a chicken farm
during her teenage years. By 15, she realized she wanted to be a doctor
and returned to England to pursue her studies at Somerville College,
A continent away though, in South America in the early 1970's, Dr.
Cassidy's life was forever changed. In 1971, Dr. Cassidy travelled to
Santiago, Chile to further her medical training. It was a time of
revolutionary change in Chile, that was shattered by the September 11, 1973
military coup led by General Augusto Pinochet. Asked by a priest to treat a
man who had been shot, and who could not go to the hospital for fear of
arrest, Dr. Cassidy provided aid. The injured man turned out to be the
second in command of the left wing forces.
Within a week, Dr. Cassidy herself was arrested by Chilean authorities.
Imprisoned for 59 days, she was stripped, tied to a bed and tortured
with electric shocks. The torture was followed by solitary confinement,
and ultimately explusion from Chile. Her treatment and other human
rights abuses resulted in the British government withdrawing its ambassador
from Chile.
In the years that followed, Dr. Cassidy suffered a hidden life of
insomnia, depression, exhaustion and fear. At the same time, her experiences
led her to become an outspoken advocate for human rights and an author
of seven books on her experiences and Christianity, including Audacity
to Believe (1977) and Sharing the Darkness : The Spirituality of Caring
One reviewer of Sharing the Darkeness wrote: "Sheila Cassidy's intent
in writing this book was to discuss what draws people to work with dying
patients. Much of the book, however, is self-revelation, as she
explores her own messy, misdirected spiritual path, sincere and devout, but
frequently meeting failure. I found myself feeling quite cheerful while
reading her book. How nice to read about the spiritual strugglings of
another, and how encouraging to see that she has attained a depth of
spirituality many people never reach, in spite of all her flaws. There's
hope for the rest of us who sincerely want to live a spiritual life, but
could never emulate the self-sacrifice of a Mother Teresa."
In her lectures, Dr. Cassidy juxtaposes the off-beat and the profound,
mixing jokes about religion and her mistakes with the importance of
faith. While held in solitary confinement, in her own words, she
"celebrated a do-it-yourself Eucharist with bread and water and made an awesome
convenant with God to do what He or She wanted for the rest of my
While still lecturing around the world and leading conferences on
justice and human rights, Dr. Cassidy found her true calling was being a
doctor. For 11 years she served as the medical director of a hospice,
mainly treating cancer patients. More recently, the focus of her work has
been on the psychological needs of patients and their families. In 1996
in Plymouth, England, Dr. Cassidy founded Jeremiah's Journey, a program
for helping bereaved children.
Eva Cassidy died tragically of melanoma at the age of 33 in 1996. Who
was Eva Cassidy? She was vocalist largely unknown outside of the
Washington, D.C. area where she lived. Painfully shy and thoroughly
uncompromising, Cassidy spent the bulk of her brief professional life playing for
a loyal following in Washington nightclubs, painting and gardening --
her two other passions -- by day.
While it is not unusual for an established artist's career to
accelerate following his or her death, it is exceptionally rare for the same to
occur for an obscure artist. But that is what has occurred based upon
word of mouth and reviews for her album entitled Songbird, released
postumously in April 1998 by Blix Street, a small, independent record label
in Los Angeles. Songbird is an anthology of cover tracks highlighting
Cassidy's vocal range from jazz to blues to rock, including powerful
renditions of Sting's "Field of Gold," Curtis Mayfield's "People Get
Ready," and ending with a version of "Over the Rainbow" that will forever
change your perceptions of the song.
Cassidy did not write many original songs. Her talent lay in
interpretation, in a mastery of emotional redefinition of a song and in finding
her path to the heart of the song often missing from its original
recording. One critic observed, "Cassidy had a voice that would silence a bar
and make pool players set down their cues. She was developing a body of
work that could have grown into the voice of a generation."

O Cassidy
O'Cassidy country, in ancient times, is found in Co. Fermanagh where
family members can be found yet today. This family served as hereditary
physicians and ollavs to the ruling Maguires. Keating cites 'Mac
Cassidy' along with MacArdell and Duffey etc. as one of the chiefs clans of
Monaghan as well.
Roderick Mac Cassidy was an archdeacon of Clogher who 'partly compiled
the Annals of Ulster'.
The 1890 index finds the family in Donegal, Dublin, Antrim and
Fermanagh. Spellings of the day in the 17th century included Cassadie in Kings
County, Cassedy in Louth, and Cassady of Donegal and Fermanagh.
O'Cassidy was also a principal name of Fermanagh.
O'Hart gives several Cassidy listings.
Patrick Cassidy, M.D. of Tyrone, Ireland and Rhode Island, U.S.A., and
Cormack O Cassida (Cassidy) is given in the barony of Glenawley in
Fermanagh with 100 acres under the plantation of Ulster. Cassidy was also
cited as 'Chief of Coole' and another of the name served in 1745 in the
Irish Brigades of France as quartermaster in FitzJames Horse Regiment.
In the first census of the United States we find the name of Casaty,
which may be an Americanization of the name.

In a survey of 1962 Cassidy was found to he the thirteenth most common
name in Co. Fermanagh and to he the fifth most common of the native
Gaelic names. The Cassidys have been in Fermanagh for over a thousand
years and up until the time of the Plantation were very prominent in the
area in the fields of literature, medicine and religion. In all the many
references to the deaths of illustrious members of the family in the
annals, only one did not die of natural causes - he was slain by an
For several centuries the O Caiside sept provided hereditary physicians
and ollavs to the Maguires. But even before the Maguires took control
of Fermanagh, the Cassidys are recorded as prominent in these fields;
the Gaelic poetry of Giolla Mochuda Mor O Caiside, died 1143, is
preserved to this day.
As erenaghs of Devenish, their chief resided at Ballycassidy (Baile Ui
Chaiside), just north of Enniskillen. From there their fame spread
throughout Ireland and, particularly in the north, Cassidys became doctors
to many other chiefs. Besides in its homeland the name is common also
in counties Donegal, Antrim and Monaghan and indeed, with the exception
of Connacht, throughout the whole island. The Donegal O'Cassidys were
erenaghs of part of Conwall in the barony of Kilmacrenan.
The Plantation destroyed their influence and thereafter little is
recorded about them save that many continued to flourish in the fields of
Gaelic scholarship and literature and in medicine right through to the
eighteenth century and, in the case of medicine, well beyond. Also,
several Cassidys were priests during the Penal period.

Caiside is an ancient Irish name. In the United States, many Cassidy
variations exist, including Cassity, Cassedy and Casada.
The name originates in County Fermanagh, Northern Ireland, where for
centuries they were prominent in the arts and fields of medicine and
religion. Like other professional families, over time they moved out to
other parts of Ulster province and all of Ireland.
The precise origin of Ui Caiside, the Cassidys, is not known. There is
a dispute as to whether they belonged to the Fir Manaigh, the first
Celtic settlers of County Fermanagh, or migrated to the area in the sixth
century A.D. during the time of St. Molaise who founded the monastery
at Devenish Island. The family was closely linked to the monastery and
had access to its school at a time when education was denied to most. In
his analysis of the family, Father P.O. Gallachair, a historian of the
region, states, "Soon the Ui Caiside name was renowned, but unlike most
ancient Irish families their fame was never won in mere physical feats
of arms, in blood and tears. Theirs was a higher, more noble fame. They
were men of peace, culture and scholarship."
From the very earliest times the Irish physician was attached to the
clan or house of a chieftain, and the profession of the physician passed
from father to son just as did the profession of the other arts and
crafts in the country. While this hereditary character of medical practice
existed in other countries, in Ireland, it persisted until
comparatively recent times. Thus, there were the Cassidys of Fermanagh, the
Callenans of Desmond, the Lees of Connaught among the leading Irish
medical families.
Cassidys served as hereditary physicians to the Maguires, the
chieftains of Fermanagh. Cassidys are recorded as physicians to the Maguires
between 1300 and 1600, and were also found practicing in the midlands of
Ireland. For example, the Annals of the Four Masters notes the death in
1504 of Pierce Cassidy of Coole in Fermanagh, "the son of Thomas,
chief physician to Maguire, a man profoundly versed in literature and
medicine, and who kept a house of general hospitality."
Although the hereditary nature of the profession created pressure for
medieval Irish physicians to reside close to their patron chieftain,
Irish physicians traveled extensively. In the 14th and 15th centuries,
many went to continental Europe for training and brought back medical
texts used centuries later. They also frequently traveled around Ireland to
exercise their skills and extend their knowledge.
In the 16th century it was more typical for Irish doctors to study in
schools established in Ireland or Scotland. Often each medical family
compiled, and handed down to succeeding generations, medical manuscripts
for their own use and for fellow doctors. From this period, Cassidys
are identified as the authors of many medical tracts. One manuscript,
written by An Giolla Glas Caiside between 1515 and 1527, still exists
and is in the library of Corpus Christi College, Oxford. It contains
scientific commentary on a wide range of topics including medicine,
philosophy, astronomy and botany. Later famous Cassidy physicians include Dr.
Felix Cassidy, who served in the Jacobite Court in France.
Cassidys were noted as "a most prominent, and is some ways a unique
house, a people apart." This acclaim stemmed in part from their long
history as priests and scholars in the Diocese of Clogher, especially during
the suppression of the Roman Catholic Church under the Penal Laws of
the 18th Century. As explained on the Irish terminology page, Catholic
church divisions did not conform to county boundaries. The Diocese of
Clogher contains most of County Fermanagh, all of Monaghan, parts of
Donegal, Tyrone, and a small piece of Louth.
The most important early Irish Cassidy priest and scholar was Ruaidhri
Caiside (Rory Cassidy, died 1541), the archdeacon of Clogher. In
1525, Caiside compiled the "Register of the Diocese of Clogher." He
also carried on the work of Cathal g MacManus, who died in 1498, in the
compilation of the "Annals of Ulster."
The Annals are one of the most significant Irish texts from the later
middle ages, containing a reliable record of events of local and
national significance along with information on family relationships, men of
learning, and social development. In the entry for 1541, it reads, "Rory
Cassidy, this is the Archdeacon of Clogher, died this year. And it is
he who wrote the greater part of this book, a man who was full of
knowledge in every science, both law and divinity, medicine and philosophy,
to the time of his death."
Less noteworthy, but certainly colourful, was Maurice Cassidy, a
Franciscan born in 1745. A contemporary claimed he was "a boisterous, fire
eating Ulsterman who was not above using fisticuffs to emphasize his
commands, and who was left in office only one year."
The contribution of the Cassidys to the priesthood originated from
their position as one of the hereditary "church families" in County
Fermanagh. Prior to 1600, large parts of Ireland, including one-sixth of the
county in the Maguire period, were owned by the church. Local families,
however, possessed the estates surrounding the churches and
monasteries. The chief of the family bore the title of "erenagh." A single church
with extensive lands might have several erenaghs, each erenagh
controlling a separate part of the church's lands.
The inhabitants of the church lands were accorded many of the
privileges of the clergy, such as immunity from secular taxation, neutrality in
time of war, and freedom from military service. With the transformation
of the Irish church in 12th century from a monastic church to one based
on a diocesan and parochial system, these lands vested in the local
In return for continuing possession of the lands, the erenaghs paid the
bishop an annual rent, many specific tributes and services, including a
night's lodging and entertainment for the bishop and his train, helped
maintain the local church and were obligated to maintain hospitality
for "pilgrams, strangers and poor travelers." The members of erenagh
families enjoyed a quasi-clerical status, and a greater part of the clergy
was recruited from these families.
The earliest renowned Cassidy poet was Giolla Mochuda Mor Caiside
(also identified as Gilla Mo Dutu ua Casaide). Before the Maguires assumed
control of Fermanagh, Caiside was famed among the fir lighinn, the
men of learning of Ireland "for all that was superior in Gaelic
literature." Caiside wrote in 1147 the poem Banshenchas (The Lore of Woman),
which tells the history of women of the world.
Still widely read and sung is the poetry of Tomas Cassidy, "An
Caisideach Ban" or the fair-haired Cassidy. Cassidy was an 18th Century
Augustian friar expelled from the friary, in his own words, "on account of
a bad senseless marriage." He spent the rest of life wandering across
Ireland and Europe as a poet and renegade priest. Cassidy's most
famous poem is An Caisideach Ban, which, as stated on one Irish album, is
"sung the length and breath of Ireland. It is the story of Cassidy, a
priest, who lusts after a fair maiden and his final wish on his death bed
would be to get a kiss from her."
Former U.S. President Bill Clinton has Cassidy ancestry - his mother's
maiden name was Virginia Dell Cassidy. President Clinton has Irish
ancestry from both parents. It is not certain, but his Cassidy roots in
America may date back five generations to Levi Cassidy (circa 1790-c1850).
As a child, President Clinton, whose father died before he was born,
lived with his maternal grandparents for several years while his mother
attended nursing school. President Clinton credits his grandfather James
Eldridge Cassidy with instilling in him a love for learning and
teaching him to read by age four.
On his 1995 visit to Ireland, former President Clinton in a speech at
College Green in Dublin observed, "My mother was a Cassidy and how I
wish she were alive to be here with me today. She would have loved the
small towns and she would have loved Dublin. Most of all, she would have
loved the fact that in Ireland, you have nearly 300 racing days a year.
She loved the horses."
On December, 12, 2000, during his final visit to Ireland as President,
Bill Clinton observed "When I started come here, you know, I got a lot
of help in rooting out my Irish ancestry. And the oldest known
homestead of my mother's family, the Cassidys, that we've been able to find is
a sort of mid 18th century farmhouse that's in Rosleigh and Fermanagh.
But it's right on the - literally right on the border. And in my
family, all the Catholics and Protestants intermarried, so maybe I was
somehow genetically prepared for the work I had to do. Maybe it's because
there are 45 million Irish Americans, and I was trying to make a few votes
at home. The truth is, it just seemed to me the right thing to do."

The Ui Chaiside
The Ui Chaiside were prominent from the fourteenth century on in
Fermanagh where many of them were hereditary doctors to Mag Uidhir chieftans.
As is the case with many learned families their origins are obscure. It
seems likely that the connection with Fermanagh went back to the
twelfth century.
A late genealogical tract traces the family through Cormac Cas,
ancestor of Dal Cais, to Mil Easpainne (Anal. Hib. 3. 136-7). The name Caiside
occurs at two points in the genealogy: eighth and fifteenth down Cormac
Cas. The earlier Caiside is given as great-grandson of Caisin (which
probably for Caisin) "a quo an Fine." The section showing the later one
is as follows: ". . . mc Ghiollamachuada mhoir mc Caiside, do bhi na
ollamh leighis agus Seannchuis tir Chaidide." It is likely that the
"Giollamachuada" of the text is the Giolla Mo Dutu who composed the metical
banshenchas in 1147 and who is described by Best and O'Brien in LL Vol.
III, p. viii, as "Gilla Mo Dutu ua Casaide." According to his own
account in the closing stanzas of the poem he composed it in Daminis ( =
Devinish on Lough Erne), but he had come from Ard Brecain ( = Ardbreccan
in Meath).
The name of the eponymous ancestor of the family is quite unusual. It
does not occur among the personal names listed in Corp. Gen. Hib. The
comment "a quo an Fine" following the name Caisin in the genealogy cited
above and the fact that the line goes back to Cormac Cas suggest that
the author of that genealogy saw a connection between Caiside (earlier
Caisite), Caisin and Cas. Also uncommon is the termination -ite, but it
is seen in the name Tipraite from which came the surname Tiobraide
(Tubridy). It is noteworthy that in an early genealogy of the Ui
Chaisin(e) branch of the Dal Cais (Corp. Gen. Hib. p. 248) a Tipraite appears
five generations down from Caisin.

Surname: Cassidy

Here is some background information which may be helpful.
Ireland was one of the earliest countries to evolve a system of
hereditary surnames. They came into being fairly generally in the eleventh
century, though some were formed as early as the year 1000. Brian Boru,
high king of Ireland, who died at the Battle of Clontarf in 1014, is
often erroneously credited with decreeing that the use of surnames should
become a requirement among his subjects. In fact the system developed
spontaneously in Ireland, as it did elsewhere, as a result of the need
for personal identification in an increasing population.

Prior to the adoption of surnames, the Irish had a system of tribal
grouping that went under formal names. These included, among others,
    Cenel Conaill, located in the north-east and traditionally
descended from Conall Gulban, son of Niall of the Nine Hostages.
    Cenel Eoghain, located in Tyrone and Derry and traditionally
descended from Eoghan, son of Niall of the Nine Hostages.

    Cenel Fhiachadh, located in the midlands and descended from Fiacha,
third son of Niall of the Nine Hostages.
    Dal gCais or Dalcassians, descendants of Cas and located in Thomond
- counties Clare and parts of Limerick and Tipperary.
    Eoghanacht, cantered in south Munster and descended from Eoghan,
son of Oilioll Olum, King of Munster.
    Siol Muireadhaigh or Silmurray, located in north Connacht.
    U Fiachrach, two groups, U Fiachrach Muaidhe, located in north
Mayo and Sligo and U Fiachrach Aidhne in south Galway.
    U Maine or Hy Many, located in east Galway and South Roscommon.

These groups were often parts of others and also subdivided so the
situation is not as simple as it might seem. For example, U Neill or Ua
Neill was a collective name for all the descendants of Niall of the Nine
Hostages. It included the northern U Neill (which in turn included
Cenel Conaill and Cenel Eoghain) and the southern U Neill (which in turn
included Cenel Fiacha and others).

The existence of these named groups indicates a predisposition among
the ancient Irish towards family grouping and naming and so it is not
surprising that the development of personal and hereditary surnames was
little more than a natural extension of this tribal system.

Prior to the coming of surnames, individuals were identified by means
of a personal name, sometimes with the addition of a nickname referring
to some deed or physical attribute, for example Con Cead Cathach (Con
of the hundred battles), Feargal Ruadh (red haired Fergal), Roisin Dubh
(dark haired Rose) and so on. The people of the time must have also
used patronymics, Eoin Mac Brian (John son of Brian), etc., but names were
not hereditary, for instance, Eamonn, the son of Eoin Mac Brian, would
be known as Eamonn Mac Eoin (son of John) rather than Eamonn Mac Brian
(Brian). However, as surnames gradually became hereditary, these
patronymics remained constant from one generation to the next.

Patronymics form the great majority of Gaelic-Irish surnames. They are
formed by adding the prefix "Mac" or "O" to the personal name of an
ancestor. "Mac" literally means "son" and "O" means grandson, but in
surnames, both are usually taken to signify "descendant of" rather than
their literal meaning. The great Irish patronymics give us quite an insight
into the popular personal names of the day, Neill, Connor, Murchadh
(hence Murphy), Aodh or Hugh (hence McKay, McHugh, O'Hea, etc.), Conall,
etc. I should mention that the use of the form Mac, Mc, M', Mag, etc. is
of no significance. All are simply variants of the Gaelic word "mac". I
should also mention that these prefixes are gender sensitive, Mac and O
being masculine. Their feminine equivalents are N (Nic if followed by
a vowel) and U.

Apart from patronymics, the other three great sources of all surnames,
not just in Ireland, are, occupational, nicknames and locative.

Surnames based on nicknames abound among the Irish. O'Sullivan is from
"suil amhain" meaning one-eyed, Deeny is from "duibhne" meaning
disagreeable, Roe from "ruadh" meaning red haired, Duff, Duffy, Deegan and
several other surnames are all derived from the root word "dubh"
(pronounced duvv or duw) meaning black.

Occupational names are somewhat less common. Clery is "O Cleirigh" from
the Irish word for clerk and McGowan (Mac Gabhan) is from the word for

Locative surnames (derived from the bearer's place of birth or where
they lived), are far less common among the Irish than the English or
Normans. However, there are some examples for instance De Gallbhaille

There are two other types of Irish surname that I should mention, both
derived by the addition of a prefix. In the first case the prefix is
"Giolla" which means "follower of", "devotee of" or "servant of". This
prefix has given rise to a large number of familiar names start with
Gil... or Kil... For example, Gilmore is from Mac Giolla Mhuire (devotee of
Mary), Kilbride from Mac Giolla Brighde (devotee of St. Bridget, Gildea
or Kildea from Mac Giolla Dhe (servant of God), Gilleran from Mac
Giolla Eanain (Eanain's servant). The second case relates to the prefix
"maol" which can have the same meaning as "Giolla", i.e. devotee, etc. but
which may also be derived from "mal" meaning leader or chief. From this
prefix we get a whole series of names beginning Mul... Mulcahy from O
Maolcathach (leader of battles), Mulderrig from O Maoildeirg (red
chief), Mulhall from O Maolchathail (follower of Cathal), Mulholland from O
Maolchalann (devotee of Saint Calann), and many more.

And so it was that by the end of the twelfth century, names derived as
explained above existed all over Ireland. However, a major event was
about to happen. In 1170, the Anglo-Normans arrived in Ireland and over
the course of a hundred years mingled and intermarried with the native
Irish. With them came a whole new selection of names and conventions.

The Anglo-Normans were mainly French speaking. Many of them were
grandchildren or great-grandchildren of those who made up the force, which
under William the Conqueror, subjugated the native English in 1066. Some
of them had already taken surnames based on their exploits in England.
For example, the leader of the invading force, Richard de Clare, better
known as Strongbow, had already derived his name from a place in
England. Other family, the D'Exeters derived their name from that town.
However, over time, a large number of these families adopted Irish ways and
Irish names. For example, the descendants of one Jordan D'Exeter
adopted the patronymic Mac Suirtain, later to become anglicised as Jordan.
The great family of Burke (de Burgo, de Burgh, de Burca) split into
several sub-septs with names like MacHugo, MacGibbon, MacSeoinin (Jennings),
MacRedmond, Mac Uilic (MacGillick) and more. The Normans also gave
birth to the famous Fitz... names, the prefix being derived from the French
"fils" meaning son. The Fitzgeralds, Fitzsimons, Fitzgibbons,
Fitzhenrys and so on, all adopted Irish customs and became "more Irish than the
Irish themselves". It is worth mentioning that not all Fitz... names
are Irish. Among the Normans of England a similar practice arose and the
Fitzalans, Fitzcharles's, Fitzgeffreys, etc. of that country are as
blue blooded as any English family, many having no connection whatsoever
with Ireland. I should also quickly mention the Fitzpatricks who are the
exception to the rule. This family is Gaelic-Irish, being Mac Giolla
Phadraigh (devotee of Saint Patrick). The name was first anglicised
Gilpatrick, but, perhaps in an attempt to make a fashion statement, the main
family adopted the Fitzpatrick form, though they have no French

The native Irish and the now naturalised Normans led a normal, if not
totally peaceful co-existence for several hundred years, during which
time many new surnames came into existence as the fortunes of families
and septs waxed and waned. However, at the start of the seventeenth
century, history took a severe turn.

Following the defeat of the Irish chiefs and the "Flight of the Earls",
English common law was enforced throughout Ireland. In an attempt to
suppress the old Gaelic order (and also the catholic religion), lands
were confiscated and granted to English and Scottish families. This
brought a whole influx of new surnames into Ireland. The new surnames of
English origin were, at first, easily spotted, with Smiths, Taylors,
Fleetwoods, etc. standing out from the established names. Ulster was mainly
settled by the Scottish and this creates no little confusion. Many of
the names that were introduced had a distinctly Gaelic flavour. Indeed
many of them were, in fact, originally Irish in origin and many more, if
not actually Irish, were similarly derived from the Scots Gaelic
language (MacDonnell is usually Scottish in origin while O'Donnell is Irish).

Further suppression of all things Irish, resulted in an insistence that
all Irish names be given an anglicised form. This resulted in a general
dropping of the "Mac" and "O" prefix and to a lesser, but still
significant, extent "Mul", "Gil" and "Kil" started to disappear. In a country
where the majority of the population spoke Irish rather than English,
it was inevitable that English-speaking civil servants would create an
amazing array of anglicised forms of the old Irish names. Some were
anglicised phonetically and others by translation (or more often than not,
mis-translation). So MacGabhain became both (Mc)Gowan (phonetic) and
Smith (translation), Mac an Tuile became Tully (phonetic) and Flood

The last century has seen a resurgence in the use of Gaelic names in
Ireland and abroad. This has resulted in a widespread readopting of Mac
and O prefixes. However, this has not always been quite consistent with
the original names. There are many examples of names that were original
of the "mac" type, being reborn with an "O" prefix. For example, Gorman
was originally MacGorman, but when found with a prefix in Ireland
today, it is usually (incorrectly) O'Gorman. One absurd example is the case
of the English name Odell (originally Odehull) being made O'Dell.

In summary, the majority of surnames found in Ireland today can be
traced to one of four major sources. These are, native Irish, Norman,
English planters and Scottish planters. There are of course others such as
surnames from Wales and continental Europe.

Based on Matheson's Census of 1890, the one hundred most common
surnames in Ireland, with their origins, at that time were
  1. (O)Murphy (Gaelic Irish)
  2. (O)Kelly (Gaelic Irish)
  3. (O)Sullivan (Gaelic Irish)
  4. Walsh (Norman)
  5. Smith  (Gaelic Irish from Mc- and O'Gowan and also English)
  6. (O)Brien (Gaelic Irish)
  7. (O)Byrne (Gaelic Irish)
  8. (O Mul)Ryan (Gaelic Irish)
  9. (O)Connor (Gaelic Irish)
10. (O)Neill (Gaelic Irish)
11. (O)Reilly (Gaelic Irish)
12. Doyle (usually Norse also a form of McDowell which is Scottish
13. (Mc)Carthy (Gaelic Irish)
14. (O)Gallagher (Gaelic Irish)
15. (O)Doherty (Gaelic Irish)
16. (O)Kennedy (Gaelic Irish)
17. Lynch (Norman and Gaelic Irish)
18. (O and Mc)Murray (Scottish and Gaelic Irish)
19. (O)Quinn (Gaelic Irish)
20. Moore  (Gaelic Irish from O'More and also English)
21. (Mc)Loughlin (Gaelic Irish also substituted for the Gaelic name
22. (O)Carroll (Gaelic Irish)
23. (O)Connolly (Gaelic Irish)
24. (O)Daly (Gaelic Irish)
25. (O)Connell (Gaelic Irish)
26. Wilson (English and Scottish
27. (O)Dunne (Gaelic Irish)
28. (O and Mc)Brennan (Gaelic Irish)
29. Burke (Norman)
30. Collins (usually Gaelic Irish but also English)
31. Campbell (Scottish but also Gaelic Irish - Mac Cathmhaoil)
32. Clarke  (usually Gaelic Irish from O'Cleary but also English and
33. Johnson (usually Scottish but also from the Gaelic Irish McShane)
34. Hughes (often English or Welsh but also a form of the Gaelic Irish
O hAodha - Hayes)
35. (O)Farrell (Gaelic Irish)
36. Fitzgerald (Norman)
37. Browne (Norman)
38. Martin (Norman)
39. Maguire (Gaelic Irish)
40. (O)Nolan (Gaelic Irish)
41. (O)Flynn (Gaelic Irish)
42. Thompson (Scottish and English)
43. (O)Callaghan (Gaelic Irish)
44. (O)Donnell (Gaelic Irish)
45. (O)Duffy (Gaelic Irish)
46. (O)Mahony (Gaelic Irish)
47. (O)Boyle (Gaelic Irish)
48. (O)Healy (Gaelic Irish)
49. (O)Shea (Gaelic Irish)
50. White (usually English sometimes used for several different Gaelic
Irish names)
51. (Mc)Sweeney (Gaelic Irish)
52. Hayes (usually Gaelic Irish from O hAodha sometimes Norman e.g. de
la Haye)
53. Kavanagh (Gaelic Irish)
54. Power (Norman)
55. (Mc)Grath (Gaelic Irish)
56. (O)Moran (Gaelic Irish)
57. (Mc)Brady (Gaelic Irish)
58. Stewart / Stuart (Scottish)
59. (O)Casey (Gaelic Irish)
60. (O)Foley (Gaelic Irish)
61. Fitzpatrick (Gaelic Irish)
62. (O)Leary (Gaelic Irish)
63. (Mc)Donnell (Scottish gallowglass in Antrim and Gaelic Irish in
Thomond and west Ulster)
64. (O and Mc)Mahon  (Gaelic Irish - two distinct septs of McMahon and
at least one O Mahon)
65. (O)Donnelly (Gaelic Irish)
66. (O)Regan (Gaelic Irish)
67. (O)Donovan (Gaelic Irish)
68. Burns (usually Scottish in Ulster but also used for Gaelic Irish
names including Byrne, Beirne, etc.)
69. (O)Flanagan (Gaelic Irish)
70. (O and Mc)Mullan  (Gaelic Irish and Scottish - from McMillen)
71. Barry (Norman)
72. (O)Kane (Gaelic Irish)
73. Robinson (English)
74. Cunningham (usually Scottish sometimes Gaelic Irish O Cuinneagain)
75. (O)Griffin (Gaelic Irish)
76. (O)Kenny (Gaelic Irish)
77. (O)Sheehan (Gaelic Irish)
78. (Mc)Ward  (usually Gaelic Irish sometimes English)
79. (O)Whelan (Gaelic Irish)
80. Lyons  (Gaelic Irish with multiple origins, also English and
81. Reid (usually English but also the anglicised forms of several
Gaelic Irish surnames)
82. Graham (usually Scottish but also the anglicised forms of several
Gaelic Irish surnames)
83. (O)Higgins (Gaelic Irish)
84. (O)Cullen (Gaelic Irish)
85. (O and Mc)Keane (Gaelic Irish)
86. King (usually English but also the anglicised forms of several
Gaelic Irish surnames)
87. (O)Meagher / Maher (Gaelic Irish)
88. (Mc)Kenna (Gaelic Irish)
89. Bell (Scottish and English)
90. Scott (mainly Scottish sometimes English)
91. (O)Hogan (Gaelic Irish)
92. (O)Keeffe (Gaelic Irish)
93. Magee (mainly Gaelic Irish sometimes Scottish)
94. (Mc)Namara (Gaelic Irish)
95. (Mc)Donald (usually Scottish but sometimes from the Gaelic Irish
96. (Mc)Dermot (Gaelic Irish)
97. (O)Moloney (Gaelic Irish)
98. (O)Rourke (Gaelic Irish)
99. (O)Buckley (mainly Gaelic Irish, O Buachalla, but also English)
100. (O)Dwyer (Gaelic Irish)

The family history information was extracted from one of more of the
following texts
"Irish Families" Edward Mac Lysaght, Irish Academic Press, 4th Edition
1985, reprinted 1991
"More Irish Families" Edward Mac Lysaght, Irish Academic Press, 1982
"Irish Family Histories" Ida Grehan, Townhouse and Country Publishers
(Ireland) and Roberts Rinehart Publishers (USA), 1993.
"The Book of Ulster Surnames", Robert Bell, 1988, Blackstaff Press,
Reprinted 1997.
"The Clans and Families of Ireland", John Grenham, 1993, Gill and
"The Book of Irish Families Great and Small", Michael C. O'Laughlin,
Irish Genealogical Foundation, 1997. Volume 1 of a multi-volume set.
Information may also be extracted from subsequent volumes.

The text may refer to the following data sources
O'Donovan: Two works, "The Tribes and Customs of Hy-Many" and "The
Tribes and Customs of Hy-Fiachrach". Published 1873 / 1874. The first work
that attempted to chronicle the origins and history of Irish surnames.
Now republished by I.G.F. ISBN 0 940134 39 X and 0 940134 38 1
Woulfe: Sloinnte Gaedheal is Gall (Irish and Foreign Names), by
Reverend Patrick Woulfe. Published 1923. The next major work relating to the
origins and history of Irish surnames. Now republished by I.G.F. ISBN 0
940134 43 8
O'Hart: Irish Pedigrees, by John O'Hart. Generally regarded as strewn
with errors and inaccuracies.
Keating, "History of Ireland". Published 19th century, now republished
by I.G.F. ISBN 0 940134 44 0
Petty's Census 1659: This was not a full census in the modern sense and
its precise purpose is not fully understood. However, it does provide a
snapshot of sorts of some names found in certain areas at the time.
Hearth Money Rolls: In the 1660's a tax known as hearth-money was
exacted. It was a charge on hearths (fireplaces); the rolls recording the
tax, therefore, indicate who lived in relative comfort as against those
who lived in unheated cabins and hovels.
Fiant: Short for "Fiant litterae patentes". Fiants were warrants to the
Chancery authority for the issue of letters patent under the Great
Seal. They dealt with matters ranging from commissions for appointments to
high office and important government activities, to grants of "English
Liberty" and "pardons" to the humblest native Irish.
Annals: These were Irish historical records kept by groups of monks.
The most important are The Annals of the Four Masters and The Annals of

The general section on Irish Surnames was written by Eddie Geoghegan.

The locations of the ancient territories, which may be mentioned in the
text, can be equated with modern counties as follows

Breffny (Breifne): Counties Cavan and West Leitrim
Corca Laoidhe: Soutwest Cork
Dalriada: North Antrim
Decies (Deise): West Waterford
Desmond (Deasmhumhan): Kerry and much of Cork
Iar Connacht: West Connaught, mainly Connemara
Muskerry (Muscraidhe): Northwest and Central Cork
Oriel (Orghialla): Armagh and Monaghan with parts of South Down, Louth
and Fermanagh
Ormond (Urmhumhan): Much of counties Kilkenny and Tipperary
Ossory: County Kilkenny and adjoining parts of bordering counties
Thomond (Tuathmhumhan): Most of Clare with adjacent parts of Limerick
and Tipperary
Tirconnell (Tir Chonaill): Donegal
Tirowen (Tir Eoghain): Tyrone with adjacent parts of Derry.

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