The popularly named "Tomb of the Julii" (Mausoleum "M") survives in the Vatican Necropolis beneath St. Peter's Basilica. The serendipitous discovery near the crypt has a vaulted ceiling bearing a mosaic depicting a solar deity with an aureole riding in his chariot, within a framing of rinceaux of vine leaves.
The surrounding Christian iconography, such as other mosaics in this tomb depicting Jonah and the whale, the good shepherd carrying a lamb (the kriophoros motif), and fishermen have led to an interpretation of the deity as Christ, known in this form as "Christus-Sol" or "Christ-Apollo". Due to these symbols, the tomb is interpreted as an early Christian vault. Allen Brent has described it as a "synthesis between Christ and Apollo", in the context of Emperor Aurelian's promotion of Sol Invictus as the chief god of the Roman Empire. According to Brent, Sol Invictus - "with whom Apollo also could be identified" - represented the "shared deity of all individual gods", and the Christian creators of the Tomb of the Julii wished to "express the metaphysical order in the cosmos in terms of a Christian syncretism".
