251

Roman Empire

 * — In the, the defeat the Romans; emperors  and  are killed.
 * In Rome,, son of Decius, succeeds Decius, while is proclaimed Emperor by the troops. Gallus accepts Hostilian as co-emperor, but an outbreak of plague strikes the city and kills the young Hostilian.
 * A fifteen-year plague begins in the.
 * Gallus concludes a treaty with the.

Europe

 * The king,, intervenes in Armenia (251–).

Religion

 * March — succeeds  as the 21st.

Deaths

 * —, (killed after the )
 * —, Roman emperor (killed during the battle of Abrittus)
 * , Roman emperor (of plague in Rome)
 * (possible date)
 * , strategist of and rival of
 * , wife of
 * , minister under
 * , general of the
 * , general of the