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,[1] 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".

[2] 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.

[3] This tomb was first discovered in 1574 when workmen accidentally broke through the ceiling while conducting some floor alterations in the basilica.