Western Christians mapped Muslim history onto apocalyptic prophecy with coded numbers

Evidence

The sect of Muhammed began in 666, and the beast of the Apocalypse bore the same number. The rise of the Ottoman empire in 1300 coincided almost exactly with the time appointed for Satan’s release and the renewed period of oppression and persecution forecast by Revelation. And it also coincided with the completed corruption of the Church under Boniface VIII. — Sophia Rose Arjana, Muslims in the Western Imagination, 279

Categorization

• XREF: Connects to the broader manufactured-image thesis: numbers and dates retrofitted onto prophecy is a mechanism of manufacturing the ‘Muslim monster’ without needing any real contact. Resonates with numerology-to-history pattern in apocalypticism.
• QUESTION: Is the 666=Muhammed claim traceable to a specific medieval source, and was it widely diffused or idiosyncratic?