The Balts:

History: it is difficult to say at what time the Balts first inhabited the Baltic area but archeologists have found skeletons dating from around 6000BC that were different from the Asian (Uralic) hunter/gatherers that sometimes visited that area; the skeletons were the remains of tall Europeans who had many similarities with the Nordic peoples in Scandinavia and northern Europe.
This early Baltic peoples originally lived in a much larger area that stretched from the Vistula to the Oka, but from the 4th century AD onwards the Balts started losing land to the Slavs who expanded their territory in eastern Europe and eventually became more powerful than them, but although the Balts took many influences from the Slavonic culture they still managed to keep their own unique identity.
During the late Middle Ages the Balts were one of the last peoples of Europe to be Christianized, in Lithuania the people even managed to keep their own religion until the 15th century, in the 14th century the Balts were defeated by Teutonic knights of the German Order and all Baltic lands came into German posession, they later regained their freedom but Prussia remained in German hands and was Germanized, which caused the culture and language of the Baltic Prussians to become extinct.
In the centuries thereafter both Latvia and Lithuania were occupied by respectively Poland, Sweden, and Russia, in 1918 Latvia and Lithuania became independant but in 1940 they were occupied by the Soviet Union; this period was one of the most devastating in Baltic history because the Soviets tried to gain permanent control over the Baltic states by performing an ethnic cleansing and destroying the native Baltic culture, over a million Russians were relocated to the Baltic states and in Latvia only 54% of the population are Latvians nowadays, in 6 of their most important cities they are even a minority, the Lithuanians form 80% of the population in their country.
In 1990 both Latvia and Lithuania regained their independance after the fall of the Soviet Union and are now able to live in freedom again.

The Baltic gods Pykuolis, Perkuno, and Potrimpo Culture: the Balts can be divided into three cultural groups; the Prussians (who are now extinct), the Latvians, and the Lithuanians.
From the 4th century onwards the Baltic culture has been highly influenced by the Slavonic culture and during the Christianization the Baltic religion was almost completely destroyed, nowadays Latvia is Protestant and Lithuania is Catholic, though Eastern Orthodoxy also plays an important role in both countries.
Some interesting information about the authentical Baltic culture and religion can be found on:

Language: the Baltic languages are very interesting for the study of Indo-European languages and some linguisticians even believe that Baltic is a direct descendant of the Indo-European root language.
The main Baltic languages were Lithuanian, Latvian, Old Prussian, Semigallian, Curonian, and Selian, Old Prussian has become extinct and Semigallian, Curonian, and Selian have been assimilated into Latvian and Lithuanian.
Nowadays the remaining Baltic languages (Latvian, Lithuanian, and some dialects of those) are spoken in Latvia, Lithuania, and a small part of northeastern Poland.
Example of Baltic languages:

(Universal Declaration of Human Rights article 1)
All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.

Religion: the Baltic religion had many similarities with the Germanic and Slavonic religions and may have taken influences from both, though it must be said that their religion also had many unique characteristics so describing it as a mixture of the Germanic and Slavonic religion would be unfair.
Religion was very important in Baltic society and the western Balts (Prussians) even had a sort of theocratic government structure that was mainly ruled by priests instead of nobles or kings.
The Balts worshipped their gods in wooden temples, sacred groves, under holy oak trees, and on hills with altars where holy fires burned (this hills were called "alkai"), most of the ceremonies were conducted by priests and magicians.
One of the most important Baltic religious centers was the Sventaragis valley in Vilnius, nowadays a Christian cathedral has been built on the site but originally this was the place where the Balts worshipped their own native gods, the main Prussian temple (which was called "Romove") was situated in northern Prussia near the modern city of Kaliningrad (Königsberg) and was also one of the most important religious places of the Balts.
In the Baltic religion there was also the belief in a world tree, but unlike in the Germanic religion this tree did not carry nine worlds, instead the top represented the sky, the trunk represented the earth, and the roots represented the underworld where perhaps the Baltic afterlife was situated.

Description of the main Baltic gods:
  • Dievu Dievs is the high god and the god of the sun and the morning light, he is also believed to have been a skygod and another name for him was Vecais Tevs, which has some similarities with the name of the Germanic god Tiwaz, both names are believed to originate from Indo-European Déiuos ("god" or "heavenly one").
    The Baltic Prussians worshipped him as a lightgod known as Swayxtix (or Zvaigzdikas in Lithuanian) who was represented as a horseman with a sword.
  • Patollo may have been a later variation of Dievu Dievs or perhaps his successor, he is the god of war, death, and the leader of the other gods, he was depicted as an old man with a long green beard wearing a turban, he often carries the skulls of a horse, cow, and human with him, Patollo also has many similarities with the Germanic god Wodan and Christian missionaries eventually equaled him to their Satan.
  • Antrimpas and Andojas are the gods of the sea, not much is known about them.
  • Pykuolis and Velinas are the gods of the dead and the underground, not much is known about them.
  • Perkuno (Latvian: Perkons or Perkonis, Lithuanian: Perkunas) is the thundergod, he was depicted as a short-tempered man with a black beard and he had many similarities with the Germanic god Þunaraz (Thunar/Donar/Thor), many historians believe that his worship was introduced by the Norse in the 6th century AD though Perkuno also has many Indo-European influences, there was a special order of priests dedicated to him and they burned an eternal fire in his honour.
  • Potrimpo / Patrimpas is the god of spring and fertility, he is also the guardian of rivers and wells, he has many similarities with the Germanic god Ingwaz/Frey and he was depicted as a young man without a beard wearing a wreath of wheat.
  • Menu / Menulis is the moongod and he is married to Saule (the sungodess), the Latvians believed that all the stars are their children except the Morningstar, which is the child of Saule en Perkuno; because of this Menu is so angry that he only appears at night when his wife is not present in the sky.
  • Saule is the sungodess and during the day she pours sunlight out of a can to grant light and fertility to the world, she is married to Menu en the snake is holy to her because it symbolizes luck and fertility, her worshippers held harmless green snakes in their houses and killing one was considered blasphemy, it was believed that a person who met a snake would get married or have a child and after the Christianization snakes were still worshipped by Lithuanian farmers.
  • Zemyna (or Zemes Mate in Latvian) is the mothergodess and the godess of fertility and the earth, the Balts may have adopted this godess from their Slavonic neighbours who worshipped an earthgodess known as Mati Syra Zemlya.
  • Ausra is the godess of the sunrise and she was sometimes also named Auska or Breksta, her name means "Eastern One" (the sun rises in the east) and it may be possible that she was connected to the Germanic godess Austrôn/Ostara.
  • Zleja is the godess of dusk, not much is known about her.

    Ancient Baltic holidays:
  • January 25: Midwinter (Pusiauziemis), this was the Baltic new year celebration in which the gods were honoured and snakes played an important role.
  • On the first thunderstorm of Spring: Spring (Velykos) started when the people had heard the first thunder of Spring, during this celebration fertility festivals were held and eggs were decorated just like in the Germanic Ostara celebrations.
  • April 23: Joré, during this day the god Perkuno was honoured and asked to grant the people fertility, Joré ("flourish") is a kenning for him that was only used in Spring.
  • On the Summer Solstice: Summer Solstice (Rasa), during this holiday the return of summer was celebrated and the people burned wheels on poles that looked much like the Germanic suncrosses.
  • During autumn: Velines / Ilges, this holiday was celebrated during the entire autumn and was dedicated to the dead and the ancestors, there are some similarities with the Germanic Jól celebration though that was held a little later.
  • December 24 and 25: Winter Solstice (Saulegriza), on this date the Balts asked their gods to help them through the winter and grant them fertility in the new year.

    The Balts in Europe