Dashed left edge = started before this timeline ·
Dashed right edge = still ongoing
Events in 284 2
235 – 284Crisis of the Third CenturyFrom 235 to 284 AD — 49 years — the Roman Empire nearly collapses. Over 50 emperors claim the throne; most are murdered by their own troops within months. The empire simultaneously faces Persian invasion in the east (Shapur I captures Emperor Valerian in 260 AD — the only Roman emperor ever taken prisoner), Gothic raids across the Danube, plague, economic collapse and the secession of the Gallic Empire (260–274 AD) and Palmyrene Empire (263–273 AD). The currency is debased by 95%; trade collapses; population falls.
284 – 305Diocletian — the great reorganiserDiocletian ends the crisis of the third century by systematically reorganising the empire. He creates the Tetrarchy — four co-emperors (two Augusti and two Caesars) ruling different regions simultaneously. He doubles the size of the army, triples the bureaucracy, reforms taxation and the currency, and fixes prices in the Edict on Maximum Prices (301 AD) — the most ambitious price control in history. He conducts the Great Persecution of Christians (303–311 AD) — the last and worst. He retires voluntarily in 305 AD — the only emperor to do so.