The Goths cross the Danube, enter the Roman dominions as far as Thrace, and capture Philippopolis.
251. Victory of the Goths; Decius, at the head of the Romans, is defeated and slain. Gallus ascends the throne.
253. Barbarians invade Mœsia and Pannonia; they are defeated by Æmilianus, who is hailed as emperor by his army; he marches against Gallus, who, with his son, is assassinated by his soldiers. On the approach of Valerian, at the head of the Gallic legions, Æmilianus is slain, near Spoleto. Valerian becomes emperor.
254. Franks invade the northern provinces of Gaul.
An eruption of Mount Ætna.
Persecution of the Christians recommences.
256. The Roman Empire is assailed on all sides. The Franks pass through Gaul and sack Tarraco in Spain; the Alemanni attack Italy; the Sarmatians and Quadi force their way into Pannonia; Macedon and Greece are ravaged by the Goths; Persians invade Syria and Mesopotamia.
Cyprian, one of the early fathers of the Church, assembles another council at Carthage, which provokes angry disputes.
258. Valerian goes into the East against the Persians. The invaders of Gaul are checked by Postumus. The Goths capture Trebizond.
260. Roman war with Persia; defeat and capture of Valerian by Sapor. Outbreaks continue throughout the provinces. Gallienus ascends the throne.