February 8 in History 421 – Constantius III becomes co-Emperor of the Western Roman Empire. 1238 – The Mongols burn the Russian city of Vladimir. 1250 – Seventh Crusade: Crusaders engage Ayyubid forces in the Battle of Al Mansurah. 1347 – The Byzantine civil war of 1341–47 ends with a power-sharing agreement between John VI Kantakouzenos and John V…