The official Sime Gen Universe Chronology can be seen at: http://www.simegen.com/CHRONO1.html
This is the document that is constantly edited as new historical events are created. It contains some fan written stories accepted into the chronology, even where every detail in the fanzine story may not seem to conform.
The Chronology is laid out on the Unity Calendar, which unlike most calendars in human history, actually has a Year Zero -- a year between the "before" years and the "after" years. This was the year during which Sime Territories and Gen Territories negotiated the first cross-border laws creating a union of Sime and Gen, avoiding Zelerod's Doom.
The table layout on the website was typed by Mary Arens from the work by Katie Filipowicz in the Paperback First Channel.
Subsequently updated by Jacqueline Lichtenberg.