Christendom would have to fight for its life

It might have appeared to any man watching affairs in the earlier years of the seventh century say from 600 to 630, that only one great main assault having been made against the Church, Arianism and its derivatives, that assault having been repelled and the Faith having won its victory, it was now secure for an indefinite time.

Christendom would have to fight for its life, of course, against outward unchristian things, that is, against Paganism. The nature worshippers of the high Persian civilization to the east would attack us in arms and try to overwhelm us.

The savage paganism of barbaric tribes, Scandinavian, German, Slav and Mongol, in the north and centre of Europe would also attack Christendom and try to destroy it.

The populations subject to Byzantium would continue to parade heretical views as a label for their grievances. But the main effort of heresy, at least, had failed so it seemed. Its object, the undoing of a united Catholic civilization, had been missed. The rise of no major heresy need henceforth be feared, still less the consequent disruption of Christendom.

By A.D. 630 all Gaul had long been Catholic.  The last of the Arian generals and their garrisons in Italy and Spain had become orthodox.

The Arian generals and garrisons of Northern Africa had been conquered by the orthodox armies of the Emperor.

It was just at this moment, a moment of apparently universal and permanent Catholicism, that there fell an unexpected blow of overwhelming magnitude and force.