Alexander the Great tops the list, not merely for his undefeated military record, but for constructing an empire spanning three continents in just 13 years. Key Comparison: While his contemporaries were still fighting for city-state hegemony, Alexander had already pushed Greek influence to the banks of the Indus. Factoring in the logistical constraints of the era, his pace of conquest was staggering—averaging an advance of roughly 10 kilometers per day. Dying at the age of 32, his legacy remains the 'Hellenistic Age,' a cultural fusion that left behind over 70 cities—many named Alexandria—which remain vital crossroads of civilization to this day.