Who Built Old St Peter’s? The Evidence of the Inscriptions and Mosaics

Old St Peter’s in Rome, according to the sixth-century Liber Pontificalis, was founded by Constantine (306–337), a claim accepted by most scholars who appeal to a variety of evidence. This paper will challenge this, focusing on the inscriptional and mosaic evidence and developing the arguments of Glen Bowersock and Alastair Logan that it was not constructed by Constantine at all but by one of his sons, in all likelihood Constans (337–350). It will argue that he began it in the late 340s as a five-aisled cemeterial basilica which Constantius II (337–361) completed in the late 350s, adding the apse mosaic. The paper will argue for the fundamental significance of two anonymous inscriptions and claim that the key evidence cited has not properly included one of them and in fact reflects the growing influence of legends about Constantine and Silvester.