A series of closely related Byzantine Greek and Latin chronicles preserve accounts of the January 749 CE Sabbatical Year earthquakes. These include Paul the Deacon, Anastasius Bibliothecarius, Theophanes, Nikephoros I of Constantinople, Megas Chronographos, Georgius Monachus, and George Cedrenus. Their accounts are not independent eyewitness reports. They were composed later and, in most cases, far from the affected region, while their similarities indicate dependence on earlier written sources and each other.

An important complication is that this Byzantine tradition preserves information concerning two earthquakes that occurred in close succession: the earlier Holy Desert Quake and the later Talking Mule Quake. The Holy Desert account describes an earthquake in Palestine, along the Jordan, and in Syria, with numerous fatalities and the collapse of churches and monasteries, particularly in the desert of the Holy City (Jerusalem). The Talking Mule account describes destruction in Syria together with landsliding and other ground effects extending into Mesopotamia. The two events may have been separated by only about 16 hours, providing ample opportunity for their effects to become transposed and conflated during subsequent textual transmission.

The Byzantine chroniclers depended upon one or more earlier sources containing information derived from the Near East. Such a source or sources is often called the "eastern source," particularly in regards to Theophanes. Williams (2024) argues that references to Syrian damage attributed by the Byzantine tradition to the Holy Desert Quake were transposed from the Talking Mule Quake during the development and transmission of the source or sources underlying these accounts. The close temporal spacing of the two earthquakes likely facilitated this conflation. Consequently, descriptions of damage throughout Syria in Byzantine accounts of the Holy Desert Quake should not necessarily be assigned to that event. Some of these effects may instead belong to the Talking Mule Quake and have migrated into the account of the earlier earthquake as the source tradition was copied, combined, and edited.

The Talking Mule Quake is described most fully by Theophanes, who reports "terrible destruction in Syria." Some cities were said to have been completely destroyed, while others were only partly destroyed. Similar descriptions occur in Nikephoros I of Constantinople, Paul the Deacon, Anastasius Bibliothecarius, Georgius Monachus, and George Cedrenus. Several versions also describe a settlement in mountainous terrain that was displaced downslope while its walls and houses remained intact. Theophanes states that the settlement "slid down entire" from mountainous positions to lower plains for approximately six miles. Nikephoros similarly describes settlements shifting from high positions and slipping down, together with their walls and houses, toward the plains below. Paul the Deacon, Anastasius Bibliothecarius, and George Cedrenus preserve variants of the same account. Although the reported travel distance is probably exaggerated, the description may preserve an account of a large earthquake-triggered landslide carrying part or all of a village downslope.