In his apostolic letter, Piis fidelium votis, dated 21 March 1453, Pope Nicholas V granted the decrepit church of St. Marina the Martyr and its precincts to a brotherhood of "Ilyrian" (South Slav) priests on the Borgo San Pietro in Rome.

[1] At this location, next to the Mausoleum of Augustus on the left bank of the Tiber, they built a guest house and a hospital,[2] and re-dedicated the institutions to Saint Jerome, a native of Dalmatia.

[citation needed] In 1582, the Society financed the publication of Aleksandar Komulović's work Nauch Charstianschiza Slovignschi narod, v vlaasti iazich ("Christian Doctrine for the Slavic People in Their Own Language").

[citation needed] At the end of the Second World War and in the immediate post-war period, the College was a prominent node in the "ratlines" used to extract Nazi and Ustaša members to Spain and South America.

In February 1947, CIC Special Agent Robert Clayton Mudd reported ten members of Pavelić's Ustaša cabinet living either in San Girolamo or in the Vatican itself.

Mudd reported: "It was further established that these Croats travel back and forth from the Vatican several times a week in a car with a chauffeur whose license plate bears the two initials CD, "Corpo Diplomatico".

The College reopened after the war when Italy and the Kingdom of Serbs, Croats and Slovenes signed the Treaty of Rome (1924) and acknowledged the clerical institution under the breve Slavorum gentem.