The Massacre of Jerusalem was a mass slaughter of thousands of Muslims and Jews by the sieging Crusaders in mid-July 1099, following the Siege of Jerusalem during the First Crusade. Contemporaneous and eyewitness sources suggest the massacre was widespread, occurring alongside the conversion of Muslim sites on the Temple Mount, including the al-Aqsa Mosque and Dome of the Rock, into Christian holy places.
Historians and eyewitness crusader accounts emphasize that the massacre was especially brutal, even by the standards of ancient and medieval warfare.