From 553 BC to 521 BC, Armenia was a subject kingdom of the Achaemenid Empire, but when Darius I was king, he decided to conquer Armenia. He sent an Armenian named Dâdarši to stop a revolt against Persian rule, later replacing him with the Persian general, Vaumisa, who defeated the Armenians in 521 BC. Around the same time, another Armenian by the name of Arakha, son of Haldita, claimed to be the son of the last king of Babylon, Nabonidus, and renamed himself Nebuchadnezzar IV.