Iran is located in Southwest Asia between the countries of Iraq, Turkmenistan, Afghanistan, and Pakistan, and the Caspian and Arabian seas. Much of the country is an arid desert plateau surrounded by mountains, including the Elburz (or Alborz) Mountains that fringe its capital city of Tehran. The predominant ethnic group are Persians, and the majority language is Persian (or Farsi).

From the early seventh century BCE until the invasion of Alexander the Great in 330 BCE, the Persian Empire, ruled by the Achaemenian dynasty, was vast and powerful, the home of sophisticated architecture, culture, and administrative practices. The prevailing religion was Zoroastrianism, based on the hymns of the prophet Zarathustra (or Zoroaster), which described beliefs incorporating astrology, magic, and reverence for a single god.

The conquest by Muslim Arabs in the seventh century CE brought Arabic language and culture as well as Shi’i (or Shia) Islam, one of the two major branches of Islamic belief (the other is Sunni). The emerging kingdom blended ancient Persian culture with Arabic influences and the Islamic religion. The dynasties that ruled Iran increasingly came into conflict with European imperial powers, spurring modernization in the 18th and 19th centuries. A notable king of the Qajar dynasty, which ruled Iran from 1789 to 1925, was Naser al-Din (r.