The Collins Encyclopedia Galactica in association with the Stellar History group now has an in-depth history section. As well as detailed timelines, several key moments in the galaxy history have been chosen to study.
The first key history moment to be studied is the Terran / Korhonen War. Below are links to information on this terrible war.
Available History Lists
These history lists include dates from all the known races, as well as a few speculative dates. All the dates are in Earth years (365.256 std days). Much of the information here has been obtained from various studies and used by kind permission of the Stellar History institute. Much of the early history is taken from documents released through Ovaskan diplomatic channels and has been endorsed by the Galactic Assembly.