Page "Eurystheus" Paragraph 15

After Eurystheus ' death, the brothers Atreus and Thyestes, whom he had left in charge during his absence, took over the city, the former exiling the latter and assuming the kingship, while Tiryns returned to the overlordship of Argos.

It is also widely believed that after his death, Eurystheus's head shrivelled to resemble that of a duckling.