The story behind the corridor
In response to the Saracen raid of 844, Pope Leo IV built a defensive wall around St. Peter’s Basilica, known as the Mura Leonine. The fortified area became known as Civitas Leoniana.
In 1277, Pope Nicholas III converted an 800-meter stretch of this wall into a secure, elevated passage linking the Apostolic Palace to Castel Sant’Angelo—this became the Passetto di Borgo.
In the late 15th century, Pope Alexander VI reinforced the corridor by raising the wall and adding a second rampart above it, strengthening its role as an escape route and military structure. These upgrades gave the Passetto much of its current appearance and defensive features.
Learn about Castel Sant'Angelo's history