Islamic Caliphate (Umayyad)

The Umayyad Caliphate expanded from the Iberian Peninsula to Central Asia by 750 AD, covering over 11 million square kilometers in just 118 years—a growth rate that outpaces #3 Roman Empire's century-spanning consolidation. It preserved Greek and scientific texts lost in Europe, translating 200+ works that directly triggered the Renaissance, a cultural contribution even the Mongol Empire's Silk Road exchanges barely matched in scholarly impact. With 80 million subjects under a unified currency and language, its governance model influenced subsequent Islamic empires.