Year 262 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Valerius and Otacilius (or, less frequently, year 492 Ab urbe condita). The denomination 262 BC for this year has been used since the early medieval period, when the Anno Dominicalendar era became the prevalent method in Europe for naming years.
After Athens surrenders following a long siege by Macedonian forces, Antigonus II Gonatas re-garrisons Athens and forbids the city from making war. Otherwise, he leaves Athens alone as the seat of philosophy and learning in Greece.
Rome besieges the city of Agrigentum which is held by Carthage under the command of Hannibal Gisco. Rome's siege involves both consular armies – a total of four Roman legions – and takes several months to resolve. The garrison of Agrigentum manages to call for reinforcements and a Carthaginian relief force commanded by Hanno comes to the rescue and destroys the Roman supply base at Erbessus. Nevertheless, after a few skirmishes, the battle of Agrigentum is fought and won by Rome, and the city falls. Gisco manages to escape to Carthage in the late stages of the battle.
After the loss of Agrigentum, the Carthaginians retire to organise their fleet. In the meantime, the Romans sack Agrigentum and enslave its Greek inhabitants. The Romans are now determined to drive the Carthaginians out of Sicily.
Seleucid king Antiochus I's eldest son Seleucus, who has ruled in the east of the kingdom as viceroy for a number of years, is put to death by his father on the charge of rebellion.
Antiochus I tries to break the growing power of Pergamum by force of arms. Eumenes I, the new ruler of Pergamum, liberates his city from the overlordship of the Seleucids by defeating the army of Antiochus I near Sardis (the capital of Lydia), and thereby establishing an independent city-state.