this is of cource, all speculation. It is based on the fact that the demons in the eclipse (in volume 13, for Griffith), said that the ceremony for a God Hands birth comes once every 216 years.
-0001-
Gaiseric becomes emperor, and eventually, the first recorded God Hand
-0217-
Void is born as God Hand, but something happens to Gaizerick...and Void is leader.
-0433-
(Conrad) is born as the 2nd God Hand
-0649-
(Ubik) is born as the 3rd God Hand
-0865-
(Slann) is born as the 4th God Hand * foxxxxy *
-1081-
The exact date of Griffiths birth as the 5th God Hand, Femto...