From Italy the new light spread over the other European countries. The Italians, everywhere surrounded by the sublime remains of Greek and Roman art, recovered first from the lethargy and confusion, caused by the great immigration of Northern nations. In Bologna, Pisa, Padua, Parma, Naples and other cities, universities and high schools were founded, where it is said, thousands of students from all countries flocked to listen to the teaching of great masters; and in this rich, inspiring and varied spectacle, Dante was the noble central figure. The development of music, in Italy, kept pace with that of literature, and its first emanations were based on the music of ancient Greece, so far as its few surviving musical hymns could be deciphered. Greece disappeared as a nation after the Roman conquest, and its music vanished at the same time. The musical revival was an entirely new departure which dated from the appearance of the early Christian converts at Rome, during the time of the Apostles. These neophytes tried to introduce the old tunes which they had heard in the holy city. But such strange melodies could not, of course, find ready adoption, and they were suppressed during the general persecutions. They were, it is true, used in the worship which was secretly carried on in the catacombs. Here they survived, transmitted from generation to generation by oral communication only, during the three centuries that preceded the formal recognition of Christianity by the state. As text and music were greatly corrupted through such transmission, Saint Ambrose, bishop of Milan, made, about the year 384, a collection of the sacred tunes then in use, trying to restore them to their original form; and he appended to the collection a code of technical laws, in order to prevent future corruptions of the music. Saint Gregory the Great made many additions (590 A. D.) to the work of Saint Ambrose, and at the same time tried to establish more comprehensive musical laws. He was the first to revive, in their completeness, the eight modes used by the Greeks, and which supplanted the four used in the time of Saint Ambrose. The collection of Gregory included, also, many new tunes and hymns, together with music to the antiphones for the entire ecclesiastical year. All this he gave in an improved mode of musical notation (Semiography), and he called this new collection "Antiphonar."