Medieval confusion about Islam stemmed from not knowing the lunar calendar

Evidence

The general failure to realise that the Muslim year is lunar, and, being shorter, moves back through the solar year, made all confusion worse. — Norman Daniel, Islam and the West, 2356

Categorization

• XREF: A concrete mechanism behind a whole genre of medieval European misreading of Islam — connects to the broader chronicle of how observers misdate religious practice. — connects to: Ignorance of the lunar calendar caused persistent confusion about Muslim feasts