Year 243 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Fundulus and Galus (or, less frequently, year 511 Ab urbe condita). The denomination 243 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.
Ptolemy III returns from his conquests of Seleucid territory with a large amount of treasure and works of art, including many statues of Egyptian gods carried off to Persia by Cambyses. He restores the statues to the Egyptian temples and earns the title of Euergetes ("Benefactor").
Drawing upon the tradition of the Spartan lawgiver, Lycurgus, the young Eurypontid king of Sparta, Agis IV, seeks to reform a system that distributes the land and wealth unequally and burden the poor with debt. He proposes the cancellation of debts and the division of the Spartan homeland into separate lots for each of its citizens. Full citizenship is to be extended to many perioeci (voteless freemen) and foreigners. In addition to pursuing these reforms, Agis seeks the restoration of the Lycurgan system of military training. Agis is supported by his wealthy mother and grandmother (who surrender their property), by his uncle Agesilaus, and by Lysander, who is an ephor (magistrate with the duty of limiting the power of the king).