Mariamne III was a daughter of Aristobulus IV and Berenice. She had three brothers, Herod of Chalcis, Herod Agrippa I, and Aristobulus V, and one sister, Herodias. Aristobulus IV was the son of King Herod and Mariamne I, a Hasmonaean princess related to the renowned Judas Maccabaeus. Some time after the death of her father in 7 BCE, Mariamne III was betrothed to Antipater II, her uncle and the eldest son of King Herod. After Antipater's execution in 4 BCE, she may have been the first wife of another uncle, Herod Archelaus, ethnarch of Judea.