The Cyrus Cylinder, which is known as "the first charter of human rights", is often seen as a reflection of the questions and thoughts expressed by Zoroaster, and developed in Zoroastrian schools of the Achaemenid era. The earliest tenets of Zoroastrian schools are part of the extant scriptures of the Zoroastrian religion in Avestan. Among them are treatises such as the Zatspram, Shkand-gumanik Vizar, and Denkard, as well as older passages of the Avesta and the Gathas.