The By No Means Mild earthquake gets its name because in some translations of Theophanes he describes it as an earthquake that was "by no means mild". Pseudo-Dionysius of Tell-Mahre, who appears to be a contemporaneous source, describes the same earthquake but provides more details than Theophanes, stating that three villages on the Khabur River in Jazira (North Mesopotamia) collapsed and many other places in Jazira were destroyed. Theophanes merely specifies that the earthquake struck Syria and Palestine. The earthquake likely struck in March 756 CE. Although calendrical inconsistencies in Theophanes' entry indicate it could have struck in the years 756, 757, 758, or, less likely, 759 CE, Halley's comet appeared in 760 CE and was described by Pseudo-Dionysius of Tell-Mahre and Theophanes four years after their earthquake accounts, thus fixing the date of this earthquake to 756 CE. There is a slight disagreement between Pseudo-Dionysius and Theophanes on the exact day the earthquake struck. Pseudo-Dionysius says it struck on the 3rd of March, while Theophanes says it struck on the 9th. Pseudo-Dionysius also says that it struck in the middle of the night and on a Tuesday. Arabic sources speak of an earthquake which struck 756, 757, or 758 CE in al-Massisah (Mopsuestia) which could be related to the earthquake described by Pseudo-Dionysius of Tell-Mahre and Theophanes. There is also a Muslim tradition that the Al-Aqsa Mosque in Jerusalem was destroyed by an earthquake that, based on textual sources, struck between 754 and 785 CE, although a more likely date range may be between 754 and 775 CE. Although some have attributed this seismic destruction of al-Aqsa to the By No Means Mild Quake, this interpretation presents several difficulties. The epicentral region inferred from Pseudo-Dionysius of Tell-Mahre’s account appears too distant to have caused the destruction of Al-Aqsa, and the proposed date for the By No Means Mild Quake may be earlier than the most plausible window for the damage in Jerusalem. It is therefore possible that Theophanes’ report of damage in Syria and Palestine reflects a conflation of two separate seismic events: the By No Means Mild earthquake affecting Jazira and northern Syria, and another earthquake responsible for damage to Al-Aqsa Mosque in Palestine.