Atossa (from Old Persian *Utauθa, and Avestan Hutaosā) was an Achaemenid queen and daughter of Cyrus the Great. She lived from 550 BC to 475 BC and probably was a sister (or half-sister) of the Persian king Cambyses II.
Atossa married Darius I during 522 BC after Darius, with the help of the nobleman Otanes, defeated the followers of a man claiming to be Bardiya, the younger brother of Cambyses II.
Xerxes I was the eldest son of Atossa and Darius. Atossa lived to see Xerxes invade Greece. Being a direct descendent of Cyrus the Great, Atossa had a great authority within Achamenian royal house and court. Atossa's special position enabled Xerxes, who was not the eldest son of Darius, to succeed his father.