Ivan Asen II of Bulgaria
Bulgarian sovereignty was reestablished with the anti-Byzantine uprising of the Bulgarians and Vlachs in 1185. The crusaders invaded the Byzantine empire, captured Constantinople in 1204 and established their Latin Empire. Kaloyan of Bulgaria defeated Baldwin I, Latin emperor of Constantinople, in the Battle of Adrianople on 14 April 1205. The reign of Ivan Asen II of Bulgaria led to maximum territorial expansion and that of Ivan Alexander of Bulgaria to a Second Golden Age of Bulgarian culture. The Byzantine Empire was fully reestablished in 1261.