ancient Egypt:

Egyptian wizards put curses on tombs; nowadays curse-breakers for gringotts try to regain treasure locked in those tombs. magic is integrated into society and wizards are held in high esteem.

about 1000 a.d. :

growing distrust on the part of muggles for wizards and witches compels the four greatest witches and wizards of the age (gordic gryffindor, helga huffelpuff, ruena ravenclaw, Salazar slytherin) to find hogwarts. Salazar slytherin built the chamber of secrets after his point of view that only pureblood wizards should be allowed into hogwarts, was dismissed. the wizarding world begins to withdraw and hide itself from muggle world.

1300s:

witch burnings; muggles were particularly afraid of magic but not very good at recognizing it.

1400s:

with the coming of renaissance and the increasing reliance of muggles on scientific reasoning, the break between the wizarding and muggle world is becoming more and more complete. each culture goes on to create their own civilization: social structures, economies, etc. each burrows a little from the other as the years go by but it becomes apparent that the muggles must be kept ignorant of the existence of their magical kin for their own good. some muggles persecute their magical neighbors, others try to exploit magical power for their own gain and for quick fixes to their problems.

1600s:

goblin rebellions in Britain. muggle persecution reaches an all time high. these are dark times for the magical community. the government of wizarding world meets to consider solutions to crisis and create the international statue of wizarding secrecy of1692. this not only completes the separation of two cultures but also lays the responsibility on the various wizarding governments in each country, for maintaining the secrecy of everything from quidditch games to dragons. over the years, for muggles, magic becomes the stuff of fairytales and legend.

1800s:

giants warred among themselves, bringing their species to the brink of extinction.

1970s:

voldemort rises to power, culminating in his battle with James and lily potter, and defeat by Harry potter (31/10/81). the giants, most of whom fought for voldemort, retreat to northern Europe.

1990s:

voldemort rises again (1994).