The Shah dynasty refers to a ruling family in Iran that played a significant role in the country's history. Established in the early 16th century, the dynasty is best known for its contributions to Persian culture, architecture, and the arts during the Safavid period. The dynasty's rulers promoted the Shia branch of Islam, which became the state religion and shaped Iran's identity. The Shah dynasty continued until the early 20th century, when political changes led to the establishment of the Pahlavi dynasty. The last ruler of the Shah dynasty, Mohammad Reza Pahlavi, faced significant challenges, including political unrest, which ultimately resulted in the Iranian Revolution of 1979.