The rise of the Komnen dynasty begins in the tenth century. The first Comnenus to sit on the throne of the Empire was Isaac I. Comnenus. After his short reign came a turbulent period in Byzantium. This situation is best exploited by the young military leader Alexius, who becomes the new Byzantine ruler. After being defeated by the Normans in 1081, Alexius succeeds in stabilizing the Empire. His reign was marked by the arrival of the Crusaders in the Empire and later successful battles against the Pechenegs and the Normans. He is succeeded by his son John II, who is considered the most successful ruler of the dynasty. He also excelled in successful military campaigns against Pecheneg, Hungary, and countries in Asia Minor. He is succeeded by his son Manuel who was also successful in his military campaigns. Manuel successfully expanded the territory of the Empire to the east and west. Many describe him as a temperamental ruler of the Western style. After him comes the infamous period of Andronicus I, he is also the last Byzantine ruler of the Komnen dynasty. After the fall of Constantinople in 1204, the brothers David and Alexius Comnenus founded the Trapezoid Empire. The Trapezoid Empire outlived Byzantium itself, although it was conquered by the Ottomans in 1461.