Doing alt-hist world building where the divergences are so random it's impossible to see what motivated the writing:

• Charlemagne's empire proves more long lasting and successfully fills the vacuum of the western Roman empire, surviving as a powerful multinational state into present day, c. 1890
• German Identity is centered on a Frankish elite nucleus.
• ile-de-france region speaks Franconian, is Insel Frankrichs. Gallo-Roman culture is majority in other French regions.
• the byzantines successfully besiege Rome in 760 and resolve the Schism in favor of the east, and the West gradually adopts Eastern style rites and organization under an autocephalous Western Orthodox Church
• the Frankish empire is usurped by a foreign Prussian dynasty in 1618, Prussians never lose their Baltic culture/language, but do administer in Franconian, and Baltic families receive privileges and stipends in exchange for imperial conscription. Different families are hereditarily archers, halberdiers, cavaliers, or sailors, but since adopting guns have for centuries been mostly non-distinct line infantry
• most Eurasian and North African cultures have an extant animal totem tradition
• a third of the human population are a infertile neuter gender identified with Lilith in abrahamic religions, that experience roles of privilege and discrimination under patriarchy.
• they grow gently swept back horns during adolescence resembling a chamois'. In some cultures the horns are surgically disbudded in childhood before they can attach to the skull.