On 10 February 1258, Baghdad was captured by the Mongols led by Hulegu, a grandson of Chingiz Khan (Genghis Khan), during the siege of Baghdad. Many quarters were ruined by fire, siege, or looting. The Mongols massacred most of the city's inhabitants, including the caliph Al-Musta'sim, and destroyed large sections of the city. The canals and dykes forming the city's irrigation system were also destroyed. During this time, in Baghdad, Christians and Shia were tolerated, while Sunnis were treated as enemies. The sack of Baghdad put an end to the Abbasid Caliphate. It has been argued that this marked an end to the Islamic Golden Age and served a blow from which Islamic civilization never fully recovered.