When did the Crisis of the Third Century begin?

The story behind the answer

235 AD is correct because the Crisis of the Third Century began with the assassination of Emperor Severus Alexander by his own troops near the Rhine. His death brought Maximinus Thrax to power and unleashed decades of military anarchy, as short‑lived “barracks emperors” rose and fell in rapid succession.

From 235–284, Rome was hammered by external invasions (Goths and the Sasanian Persians—Emperor Valerian was captured in 260), internal breakaway states (the Gallic and Palmyrene Empires), economic collapse from coin debasement, and plague. Stability returned only with Diocletian’s reforms. Memory tip: “Severus Alexander was severed in 235,” marking the start of a third‑century, 50‑year free‑for‑all.