Christians projected a Venus-cult origin onto the Muslim Friday prayer

Evidence

To the Latins the salient point about the Friday prayer was often that Friday was the day once sacred to Venus, and in this view the Muslims had once, before Muhammad, worshipped her, and still now treated her day as holy, or even still worshipped her on that day; or, more simply, it was said that it was appropriate that the religion which chiefly served venery should celebrate the day of Venus. — Norman Daniel, Islam and the West, 1184

Categorization

• ADDENDUM: Fits the ‘Complaints About Immodesty’ article’s theme of Christian projection onto Muslim practice — the Venus/sexual-laxness framing of Islamic devotion is a doctrinal twin of the dress-panic moralism already in that piece.
• SEED: Angle: the ‘Islam as religion of sexual license’ trope has a medieval genealogy reaching back to misreading the Friday prayer as a relic of Venus worship.