In the fourth century of the Christian era Roman civilization expired; Western Europe was invaded by the barbarians; letters and science sought the last refuge at Alexandria; the Middle Age commenced. Greek medicine strove to survive the revolution in the city of the Ptolemies and even produced a few celebrated physicians, i.e., Alexander Ætius, Alexander Trallian, and Paulus Ægineta, but at the end of the seventh century, the school of Alexandria also fell and disappeared in the clouds of a false philosophy, bequeathing all Hippocratic traditions to the Arabs, who advanced as conquerors to the Occident.