Ardashir I or Ardeshir I (Middle Persian: 𐭠𐭥𐭲𐭧𐭱𐭲𐭥, Modern Persian: , '), also known as Ardashir the Unifier (180 – 242 AD), was the founder of the Sasanian Empire. He was also Ardashir V of the Kings of Persis, until he founded the new empire. After defeating the last Parthian shahanshah Artabanus IV on the Hormozdgan plain in 224, he overthrew the Parthian dynasty and established the Sasanian dynasty. Afterwards, Ardashir called himself "shahanshah" and began conquering the land that he called Iran.