Ptolemy III Euergetes
Despite the lack of precise sources, the outlines of Callimachus's working life can be gathered from his poetry. Poems belonging to his period of economic hardship indicate that he began writing in the 280s BC, while his poem "Aetia" shows signs of having been composed in the reign of Ptolemy III Euergetes, who ascended to the throne in 246 BC. Ferguson writes that Callimachus stopped writing and died at some point after 240 BC.