Gonnella (2006:168–169) reports that excavations in the Citadel of Aleppo uncovered some non-military Byzantine and Umayyad remains, but overall only “very few” pre-Ayyubid traces. She does not mention any seventh-century archaeoseismic evidence, though she does cite Ibn al-Shihna (al-Durr al-muntakhab, 40), who wrote that Muslim conquerors rebuilt the citadel walls after they had been ruined by an earthquake. Ambraseys (2009:220) cautions that “the date of this earthquake, for which there are no contemporary sources, is problematic.” Guidoboni et al. (1994:356) quote Ibn Shaddad (1145–1234 CE), who lived in Aleppo for nearly forty years, as stating that “before Abu ‘Ubayda conquered Aleppo (in A.H. 15 – 14 Feb. 636 to 1 Feb. 637 – verified with CHRONOS) there was a severe earthquake, which caused the citadel and the walls to collapse.” Ambraseys (2009:115–116) also records that Aleppo native Kemal ad-Din (1193-1262 CE) wrote that “when Abu Obeidah took Aleppo, the walls of the city, as well as those of the citadel, had to be repaired and in parts rebuilt, having been thrown to the ground before the conquest of the city (Ibn Habib, Durr. 31).” Ambraseys (2009:115–116) continues that “Abu Obeidah captured Aleppo in the spring or summer of AD 638 after considerable efforts had been made to scale the fortifications of the citadel, which were impregnable (Blochet 1895, 548).” He concludes that this makes it seem “unlikely that the earthquake occurred before the conquest of the city.”