Alexios I Komnenos (Alexius I Comnenus) is crowned Byzantine emperor. He inherits an empire that is collapsing, but under his rule the Komnenian dynasty achieves its full power and the decline of the Byzantine empire stops.
He is always under pressure from Turks in the east and Normans in the west. It's the Seljuq Turks which pose the most serious danger, though, causing him to seek assistance from the pope in Rome. The result is Pope Urban II calling for the first Crusade.