Zoroastrianism is a monotheistic religion. It takes its name from its founder, Zaratustra (or Zoroastro), or from the main god, Ahura Mazdā from which the name of Mazdaism. His sacred text is the Avestà, which collects various contributions of various origins accumulated over the centuries. Of it only the Gāthā (religious songs) are directly attributable to the prophet Zarathustra. Zoroastrianism developed and spread as the main religion, both theologically and demographically and politically, in the Iranian and Central Asian regions, until the advent of Islam, that is, until the Arab conquest of the Persian Sasanian Empire in the middle of the 7 century. Small Zoroastrian communities remain today in Iran, India, Pakistan, Tajikistan and Azerbaijan. The Zoroastrian diaspora comprises two main groups: the Parsis of the South Asian environment and the Zoroastrians of Iran. The latter survived in Iran for centuries of persecution, like other religious minorities. Zoroastrian communities exist in Tehran, Yazd and Kerman, where many still speak a dialect different from the Iranian language. The Zoroastrians in Iran are the oldest religious community in the country. Currently there are about Zoroastrian 60.000 in Iran. The Zoroastrians, the Armenian, Assyrian and Persian Jewish communities are officially recognized by the 1906, and each of these minorities is assigned a seat in the Iranian Parliament. So far the Iranian people still maintain many traditions of Zoroastrian worship as the main spring festivals which is regarded as the beginning of the new year (Il Nawruz). The world population of Zoroastrians is estimated between the 300.000 and the 350.000 units. UNESCO has proclaimed the 2003 year of the "3000º anniversary of Zoroastrian culture" with special events around the world.