A.C. 171:
Born.

A.C. 193:
Becomes leader of Romefellor's secret society, OZ.

A.C. 195:
Leads OZ rebellion against Alliance. Romefellor now in control.
First duel with Wufei. Treize wins and decides the next fight should be with Wufei's specialty, MS.
Disagrees with Duke Dermailles and Col. Tuberov's idea of using MD in combat.
After Romefellor decides to continue using MD, resigns from his position as leader of OZ. Is confined to the Romefellor Foundation Headquarters.
Moved to estate in Luxenbourg. There, he designs and builds the Gundam Epyon, which he gives to Heero Yuy.
Takes leadership of World Nation from Relena.
Leads massive battle against White Fang in Tallgeese II. During the battle, he has his second duel with Wufei, and this time, Wufei wins, destroying Tallgeese II and killing Treize. His death causes a grief-stricken Lady Une to surrender, ending the battle for everyone except Zechs and the Gundam pilots.