The Seljuk Empire, or the Great Seljuk Empire, was a high medieval empire, culturally Turco-Persian, founded and ruled by the Qïnïq branch of Oghuz Turks. It spanned a total area of 3.9 million square kilometres (1.5 million square miles) from Anatolia and the Levant in the west to the Hindu Kush in the east, and from Central Asia in the north to the Persian Gulf in the south. The Seljuk Empire was founded in 1037 by Tughril (990–1063) and his brother Chaghri (989–1060), both of whom co-ruled over its territories; there are indications that the Seljuk leadership otherwise functioned as a triumvirate and thus included Musa Yabghu, the uncle of the aforementioned two. From their homelands near the Aral Sea, the Seljuks advanced first into Khorasan and into the Iranian mainland, where they would become largely based as a Persianate society. They then moved west to conquer Baghdad, filling up the power vacuum that had been caused by struggles between the Arab Abbasid Caliphate and the Iranian Buyid Empire. The subsequent Seljuk expansion into eastern Anatolia triggered the Byzantine–Seljuk wars, with the Battle of Manzikert in 1071 marking a decisive turning point in the conflict in favour of the Seljuks, undermining the authority of the Byzantine Empire in the remaining parts of Anatolia and gradually enabling the region's Turkification. The Seljuk Empire united the fractured political landscape in the non-Arab eastern parts of the Muslim world and played a key role in both the First Crusade and Second Crusade; it also played an important part in the creation and expansion of multiple art forms during the period in which they had influence.By the 1140s, the Seljuk Empire began to decline in power and influence, and was eventually supplanted by the Khwarazmian Empire in 1194. Source: Wikipedia (en)