The Seljuks went on to establish an empire in Iran that soon extended to Mesopotamia, where Tughril captured Baghdad in 1055 and assumed the titles of sultan and shahanshah (shah of shahs). His nephew and successor, Alp Arslan (1063–1072), defeated and captured the Byzantine emperor in the battle of Manzikert (Malazgird) and opened Anatolia to Turkish migration. His son, Malekshah (1072–1092), completed the conquest of Syria in 1084. The empire thus extended from the Oxus to the Mediterranean. It is known as the empire of the Great Seljuks , and remained unified for some half a century.