Ka'ba-ye Zartosht (meaning the "Cube of Zoroaster") is a 5th-century B.C Achaemenid square tower. The structure is a copy of a sister building at Pasargadae, the "Prison of Solomon" (Zendān-e Solaymān). It was built either by Darius I (r. 521–486 BCE) when he moved to Persepolis, by Artaxerxes II (r. 404–358 BCE) or Artaxerxes III (r. 358–338 BCE).