Christian thinkers consoled themselves that Islam’s rise was prophesied

Evidence

The prophecy of Methodius foretold that the Arabs, for the sins of the Christians, would leave the desert in such numbers and strength as to dominate the world until a king should arise to free the Christians and subdue the Ismaelites in their turn. This seemed to have been realised when merciful God scattered the Arabs by Charles the Great; if the prophecy were to be trusted, it could not happen again. — Norman Daniel, Islam and the West, 721

Categorization

• XREF: connects to: Humbert rationalized Islam’s rise as God’s permitted evil producing three goods