The black Abbasid and red European flags both shifted from revolution to regime symbols

Evidence

A classical example was the black flags of the Abba¯sids. Like the red flag in Europe a millennium later, it first appeared as a call to revolution, and was transformed into an emblem of the ruling regime. — Bernard Lewis, From Babel to Dragomans, 484

Categorization

• XREF: Parallels the analysis of flags, beards, and dress as political signaling in ‘Complaints About Immodesty Go Way Back.’