Amalasuntha (ă´mələsŭn´thə), d. 535, Ostrogothic queen in Italy (534–35), daughter of Theodoric the Great. After her father's death (526) she was regent for her son Athalaric. He died in 534, and she and her husband, Theodahad, became joint rulers of Italy. Her friendly relations with the Byzantine emperor Justinian I alienated her people. In 535 the Ostrogoths revolted; Amalasuntha was exiled and later murdered by order of her husband. Justinian used her murder as his pretext for attacking and reconquering Italy.