The Basilica of San Clemente with its mosaic and frescos is a jewel of middle age, renaissance and baroque artworks.
Then you walk down the first staircase, and you “travel” into the 4th century CE.
It is just amazing how you can see and touch a period between the IV and the XI century. Through the frescos you discover the importance of Cirillo and Metodio and the change from Byzantine to Roman style.
Inscriptions and tombstones of the Roman Empire – and a copy of a Mithraic Altar in the southern aisle… which leads you to the next layer – another staircase and to the I as well art to the III century CE – were the real mithreum with its altar was hidden. Implanted in a Roman Insula of the I century. The religion that lost the competition again Christianity.