The 3 biggest threats to the Roman Empire | Anthony Kaldellis and Lex Fridman

In this discussion with Lex Fridman, historian Anthony Kaldellis provides a framework for understanding Roman Empire history by identifying three major crisis points that caused swift territorial loss. The Arab conquests in the 630s resulted in the loss of significant territory within a single decade. The Seljuk Turkish conquest of Asia Minor in the 1070s was similarly rapid, though partially reversed. The Fourth Crusade in 1204 saw Western armies sack Constantinople and fragment the empire, though recovery eventually followed.

Kaldellis emphasizes that these dramatic defeats, while terrible, actually represent exceptional moments in Roman history. The broader narrative is one of slow but steady economic growth, territorial consolidation, and societal regrouping. This creates a methodological tension that historians must carefully navigate: recognizing when major disruptive events occur while understanding that most historical development happens gradually.

To illustrate this methodological point, Kaldellis discusses how historians use conventional dates to mark processes rather than discrete events. Constantine's conversion to Christianity is presented as a rare example of an individual decision with unpredictable long-term consequences. In contrast, the 395 date for the division of the Eastern and Western Empires is merely a conventional marker for what was actually an ongoing process of jurisdictional allocation among emperors, with the empire subsequently reuniting and dividing again. Similarly, the 476 date for the fall of the Western Empire obscures the reality that this decline was a decades-long process rather than a singular event.