Just before sunset on Thursday 6 December 1033 CE1, a powerful earthquake struck Palestine. Strong aftershocks are reported to have continued for the next ~24–36 hours. The precise date and time come from an eyewitness account preserved in a letter in the Cairo Geniza. The witness experienced the earthquake in Ramla, where many structures collapsed and numerous residents died. A second earthquake may have struck around 17 or 18 February 1034 CE—dates reported by the contemporary author George Cedrenus and the later historian John Skylitzes. Jerusalem suffered heavy damage, with widespread collapse and the destruction of the al-Aqsa Mosque, which subsequently had to be rebuilt. Other locations mentioned as damaged include Hebron, Jericho, Ascalon, Gaza, the Negev, Nablus and its surroundings, Tiberias and its region, the district of Banias, Syria, Palestine as a whole, and Akko, where a tsunami is also reported. More than a dozen Hebrew, Greek, Persian, Arabic, and Syriac authors provide a rich corpus of seismic effects, complemented by an array of archaeoseismic and paleoseismic evidence.