The Basilica of Saint Sylvester the First also known as (Italian: San Silvestro in Capite, Latin: San Silvestri in Capite) is a Roman Catholic minor basilica and titular church in Rome dedicated to Pope Saint Sylvester I. It is located on Piazza San Silvestre, on the corner of Via del Gambero and the Via della Mercede, and stands adjacent to the central Post Office, while across the Piazza stands Santi Claudio e Andrea dei Borgognoni.
Built in the 8th century as a shrine for the relics of the saints and martyrs from the Catacombs, the church is the National church of Great Britain. The Latin words "in capite" refers to the canonical title of Pope Sylvester the First, to which in capite means in First, in Chief, or in Head. By honorific coincidence, the basilica is also famous for enshrining a fragmented head purported to be Saint John the Baptist, putatively kept as a relic, in a chapel to the left of the entrance.Wikipedia