Sack et al. (2010) report that the construction of Basilica B began in spring 518 CE, at the end of the reign of Emperor Anastasius I (r. 491–518 CE) and was probably completed under Emperor Justin I (r. 518–527 CE). They state that the basilica was soon severely damaged by an earthquake, after which it was not rebuilt and instead abandoned. Stratigraphic relationships with other buildings in Resafa, where spolia from Basilica B were reused, indicate that this destruction took place before the middle of the 7th century and certainly before the construction of the Great Mosque in the second quarter of the 8th century. Some parts of the basilica remained in use for a time, and houses were later built over the abandoned sections, with occupation continuing until the city’s abandonment in the 13th century. Intagliata (2018:112) likewise reports seismic destruction at Resafa, noting that Basilica A had been ruined by an earthquake not long after its construction. Spolia from this damaged church were later reused in the construction of a transept-type mosque built after the accession of Hisham b. ʿAbd al-Malik (r. 724–743 CE) in 724 CE, as well as in a nearby suq.

Kázmér et al. (2024:35–36) constrain the date of this earlier earthquake more closely, suggesting it occurred between the consecration of the church (Basilica A) in 559 CE and about 579 CE. They note that the sweeping arches of Basilica A (aka St. Sergius or Holy Cross Basilica) had to be underpinned and subdivided by a second set of arches within roughly twenty years of the initial construction, indicating that lateral shaking had deformed the original arches. They also report that the nave was surrounded by massive buttresses, possibly as part of the same reconstruction effort.

Kázmér et al. (2024:36) further suggest that another earthquake may have struck after this initial event but before the Sasanian sack of the city in 616 CE during the Byzantine–Sasanian War (602–628 CE). They cite evidence such as dropped keystones and voussoirs, in-plane extension, and out-of-plane extrusion of individual ashlars and entire walls, which they interpret as indicating an intensity of IX. Certain deformations could also reflect differential subsidence rather than seismic action alone.