The (Roman Catholic) Franciscan Church of St. Catherine of Alexandria was built in 1882 on the ruins of the Crusader church and monastery belonging to the Augustinians. The colonnade of the present atrium (designed in 1948 by Antonio Barluzzi) incorporates surviving elements of the medieval cloister.
Beneath the paving of the cloister are the foundations of an earlier Byzantine monastery, possibly that of St. Jerome.
A door in the southwest corner of the cloister leads into a Crusader chapel. The room was created in the 12th century when the Crusaders walled off the north end of the Justinian narthex to construct a bell tower (no longer extant). The chapel walls are decorated with remnants of Crusader wall paintings, which were partially restored in 1950.
A narrow stairway in the south aisle leads down into a complex of caves and rock-cut chambers, which contain a number of chapels. One of these is popularly identified as the room in which St. Jerome translated the Bible from Hebrew and Greek into the Latin Vulgate, starting in the year 384. A short passage from one of the adjoining chambers leads into the Grotto of the Nativity, but the door giving access is usually locked.
Sources: Israeli Foreign Ministry