Europe was not a creation of the Roman conquest. Nevertheless, during the reign of Pepin the Short in the eighth century, the horizons of the economic world, like those of the political world, still followed the lines of the Roman Empire. The Mediterranean countries remained more or less intact, although, from the third century, migrations from the steppes to the east were beginning to cause some problems. Constantine reinforced this unity around two poles: Rome and Constantinople. Though shaken by the first rumblings of the Arab conquest, it was revived for a time by Justininian. In the seventh and even the eighth centuries an Eastern presence was as marked in Gaul as in Italy and Spain. "Syrian" merchants were to be found not only in the ports along the Mediterranean coast but also inland in towns as far apart as Paris and Lyons, Bordeaux and Orleans. Eastern religions had invaded the West: Mithraism with its dualistic belief in good and evil, and Christianity with its mystery of redemption. The earliest forms of Western monasticism were influenced—in Marseilles, Hyères, Lérins, and Arles—by ideas borrowed from the tradition of religious communities in the East. The West was introduced to the monastic rule of the Egyptian St. Pachomius through St. Jerome's translation, while Caesarius of Arles, whose rule was written around the year 500, took his inspiration from practices introduced from the eastern Mediterranean into Lérins a century earlier. The political ideas of St. Augustine, the Berber bishop of Hippo in Algeria from 398 to 430, renewed intellectual life in the Latin world. Berber law was not so very different from Theodosius's simplified version of Roman law.
All this time merchants had continued to travel to and fro along the trade routes of the West. They brought back with them from further east