Henri Pirenne — Belgian Historian born on December 23, 1862, died on October 25, 1935

Henri Pirenne was a Belgian historian. A medievalist of Walloon descent, he wrote a multivolume history of Belgium in French and became a national hero. He also became prominent in the nonviolent resistance to the Germans who occupied Belgium in World War I... (wikipedia)

The cause of the break with the tradition of antiquity was the rapid and unexpected advance of Islam. The result of this advance was the final separation of East from West, and the end of the Mediterranean unity.
The Germanic invasions destroyed neither the Mediterranean unity of the ancient world, nor what may be regarded as the truly essential features of the Roman culture as it still existed in the 5th century, at a time when there was no longer an Emperor in the West.
The Germanic invasions in the West could not and did not in any way alter this state of affairs.