Zend-Avesta is the religious book of the Persians who professed the creed of Zarathustra, known in classic and modern times as Zoroaster. Zoroaster is to be classed with such great religious leaders as Buddha and Mohammed. He was the predecessor of Mohammed and the worship and belief which he instituted were trampled out in Persia by the forces of Islam in the seventh century of our era. The Persian Zoroastrians fled to India, where they are still found as Parsis on the west coast of Hindostan.