A Basilian monastery 2.5 miles from Frascati, Italy, founded 1004 by Saint Nilus, a Calabrian Greek, who obtained the site from Gregory, Count of Tusculum. Extensive possessions were bestowed upon the abbey, and its head was created Baron of Rossano, with a fief. Opposing factions brought much trouble to the monastery between the twelfth and fifteenth centuries. In 1608 it became a member of the Basilian congregation established by Pope Gregory XIII, and in 1881Pope Leo XIII restored the Greek Rite at the abbey, which has always been a center of Greek learning. Declared a national monument, 1874, it was raised to the rank of a Roman basilica, 1903. About 1905 the archaeologist Lanciani discovered catacombs near Grottaferrata which had remained untouched since the early days of the Church. These were acquired by the abbey and excavations begun in 1912 yielded much of interest.