This human multitude once put in motion, nothing was able to stop it, neither the military tactics of the legions nor the defeats which it suffered; neither rivers nor mountains, nor the dangers of unknown seas. The Franks, before settling in Gaul, traversed it once from end to end, crossed the Pyrenees, ravaged Spain, and disappeared in Mauritania. Transported once in great numbers to the shores of the Euxine Sea, and imprudently entrusted by the Romans with the defence of their frontiers, they embark, pillage the towns of Asia and Northern Africa, and return to the mouth of the Rhine. Their expeditions intercross each other; we find them everywhere at once; Franks are seen at London, and Saxons at Angers. In 406, Gaul is overrun with barbarians, Vandals, Saxons, Burgundians, Alemanni; every point of the territory is in flames; the noise of a falling empire reaches St. Jerome, in his cell at Bethlehem, and in an eloquent letter he deplores the disaster of Christendom: "Who could ever have believed the day would come when Rome should see war at her very gates, and fight, not for glory but for safety? Fight, say I? Nay, redeem her life with treasure."[31] Treasure did not suffice; the town was taken and retaken. Alaric sacked the capital in 410, and Genseric in 455. During several centuries all who emerge from this human tide, and are able to rule the tempest, are either barbarians or crowned peasants. In the fifth and sixth centuries a Frank reigns at Paris, Clovis to wit; an Ostrogoth at Ravenna, Theodoric; a peasant at Byzantium, Justinian; Attila's conqueror, Aetius, is a barbarian; Stilicho is a Vandal in the service of the Empire. A Frank kingdom has grown up in the heart of Gaul; a Visigoth kingdom has Toulouse for its capital; Genseric and his Vandals are settled in Carthage; the Lombards, in the sixth century, cross the mountains, establish themselves in ancient Cisalpine Gaul, and drive away the inhabitants towards the lagoons where Venice is to rise. The isle of Britain has likewise ceased to be Roman, and Germanic kingdoms have been founded there.