The remains of two brothers from Thessalonica, St Cyril (who is particularly venerated by the Czech community) and St Methodius, are preserved within the basilica to this day. After translating the Slavic liturgical texts, they came to Rome in 863 to seek the approval of Pope Adrian II.
Shortly after their arrival, Cyril fell ill, but decided nonetheless to enter the monastery of Greek monks at the Basilica of Santa Prassede, where he died in 869 at the age of 42. Methodius, eventually obtained permission to bury his brother’s remains in the Basilica of San Clemente, so that Cyril might rest next to Pope Clement, whose relics he had brought to Rome.
The present church was erected around the 12th century over the foundations of various buildings, which had been built one on top of the other over the centuries and which date back, at the lowest level, to the 2nd century AD.
