This video by Caspian Report discusses the Islamic conquest of Persia (Present-day Iran) during the 7th Century AD. The rise of Islam as a religion coincided with significant political, social, economic and military weakness in Iran, which was then under the rule of the Sassanid Empire. The Arab armies initially attacked Iran in 633 through the province of Asōristān (present-day Iraq). After a 21-year long campaign, the Sassanid Empire collapsed in 654 to the Arab forces under the leadership of Uthman ibn Affan. The conversion of the Iranian people to Islam gradually took place over the next four hundred years and was relatively easy due to the fact that Zoroastrianism (the main religion in Iran) was similar in many ways to Islam. Additionally, the Arab conquest of Iran is mentioned to have ultimately strengthened Islam and allowed it to become a major world religion that has endured. On the other hand, the Arab conquest is one of many examples of a foreign imperialist invasion force attempting to invade Iran and weaken its culture. Additionally, the Arab conquest of Iran is mentioned to have prevented the emergence of a strong and independent Iran until the rise of the Safavid Empire in the early 16th Century.