The last great war of the ancient world | Anthony Kaldellis and Lex Fridman

The conversation examines the last great war of the ancient world between the Byzantine (Eastern Roman) and Persian empires from 602-628. Initially, the Persians conquered the Roman Eastern provinces—Syria, Palestine, and Egypt—causing massive revenue loss and strategic vulnerability. Rather than defending against Persian armies besieging Constantinople in 626, Emperor Heraclius spent approximately 15 years preparing unconventional campaigns that struck into the Persian heartland through the Caucasus and Mesopotamia. This strategy, aided by Turkish allies, degraded Persian infrastructure and ultimately triggered a coup that killed the Persian shah Khosrow II.

Kaldellis explains the differing motivations of the three powers involved. Khosrow II pursued a revanchist vision of extending the Persian Empire to the Mediterranean, recalling the ancient Achaemenid Empire. For Rome, it was purely defensive survival. The Arabs initially sought to unify Arabia under Islam, then opportunistically struck both weakened empires from an unexpected direction—Arabia—for which neither empire had prepared defensive strategies.

The Arab conquests succeeded rapidly because both empires were exhausted, depleted of manpower and resources from their mutual war. The loss of Egypt was particularly catastrophic for Constantinople, eliminating the grain supply that sustained the capital's population. Recovery was extraordinarily slow, taking centuries. The empire first had to 'stop the bleeding' by holding defensive lines through the 7th century until the 660s-670s, when they began gaining ground. Military innovation proved decisive: the development of Greek fire—a secret flammable compound deployed through pressurized containers with nozzles—was used both against Arab naval attacks and later against Viking raiders in the 940s-1040s. Greek fire was so effective that it functioned as a nuclear-level deterrent. The empire eventually stabilized by withdrawing forces to Asia Minor, fortifying it heavily, and implementing a new militarized administrative system to support and provision armies.