by the 13th century the blank was the largest land empire at that point
Empire In the thirteenth century, Genghis Khan expanded the Mongol Empire to be the largest contiguous empire in the world. However, within two generations, the empire was separated into four discrete khanates under Genghis Khan's grandsons. One of them, Kublai Khan, conquered China and established the Yuan Dynasty with the imperial capital at Beijing. One family ruled the whole Eurasian land mass from the Pacific to the Adriatic and Baltic Seas. The emergence of the Pax Mongolica had significantly eased trade and commerce across Asia.[25][26]
Byzantine Empire The borders of the Empire evolved significantly over its existence, as it went through several cycles of decline and recovery. During the reign of Justinian I (r. 527–565), the Empire reached its greatest extent after reconquering much of the historically Roman western Mediterranean coast, including North Africa, Italy, and Rome itself, which it held for two more centuries. During the reign of Maurice (r. 582–602), the Empire's eastern frontier was expanded and the north stabilised. However, his assassination caused the Byzantine–Sasanian War of 602–628, which exhausted the Empire's resources and contributed to major territorial losses during the Early Muslim conquests of the seventh century. In a matter of years the Empire lost its richest provinces, Egypt and Syria, to the Arabs.[5]