After Chaos

After Chaos (abbreviated as OT)p42 defines the epoch in Titan's history that began with the ending of the Chaos Wars which themselves marked then end of Old Time.

End of the Chaos Wars
The Chaos Wars, referring to the War of the Wizards and the Great War against Evil, had caused so much destruction and had poisoned so much of the land that their ending, in 1998 OT was deemed to mark the end of Old Time. What would have been 1999 OT, was instead taken as Year One of the New Age and named 1 AC.

This is teh predominant dating system used across Titan although by no means is it the only one.