Events

By place

Roman Empire

• Gallienus becomes Emperor.
• Gallienus defends what remains of the empire against barbarians and usurpers. He reorganizes the army and reforms the administration.
• Gallienus reinforces the military and establishes a new mobile force supported by the cavalry, which becomes the pivot of the Roman army. The army's headquarters are established in Milan.
• The Roman fort of Wiesbaden (Germany) is captured by the Alamanni (possibly 259).
• Franks take control over the Scheldt estuary (approximate date).

Asia

• Persian king Shapur I destroys Caesarea Mazaca in Asia Minor.
• Cao Huan succeeds Cao Mao as ruler of the Chinese Kingdom of Wei.
• Syria, Egypt and Palestine break off from the Roman Empire to form the Persian-supported Palmyrene Empire.

By topic

Arts and sciences

• Earliest known date of chess.

Religion

• Paul of Samosata becomes Patriarch of Antioch.

Births

• Emperor Hui of Jin China (approximate date)

Deaths

• Cao Mao, ruler of the Chinese Kingdom of Wei (killed in an abortive coup d'état against Sima Zhao)
• Emperor Valerian I (approximate date)
• Sun Liang, emperor of the Chinese Kingdom of Wu
• Chen Tai, minister of the Kingdom of Wei