ABSTRACT
When in Rome, Father Leonard Boyle lived at the Collegio San Clemente. A room was kept for him beside the upper salone, even when he was resident in Toronto. As Prefect of the Vatican Library, he was entitled to an apartment in Vatican City, but he preferred to stay at San Clemente and commute to the Library every day by bus. San Clemente featured prominently in Fr Boyle's publications. His Short Guide has helped innumerable tourists understand the complexities of the site. After a brief reference to the medieval rebuilding of the church, the mosaics of the arch and then the apse will be analyzed, in the light of comparable ancient, early Christian and medieval works, in order to explain their artistic and theological significance. Below the crucifix a luxuriant acanthus plant spreads its scrolls through the apse, with slender stalks twisted into two ovals to frame Mary and St John, and the upper part of the cross.
