(c. 978-1050) Byzantine empress who ruled from 1028 until 1050. She gained the title by marriage to the heir apparent Romanus III Argyrus, but was reputed to have poisoned him (1034) in order to marry her lover Michael. He died 1041 and Zoë and her sister Theodora were proclaimed joint empresses. Rivalry led to Zoë marrying Constantine IX Monomachus with whom she reigned until her death.