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 was gradual and incentivized in various ways over 400 years with some Iranians never converting and widespread cases of the destruction of cultural artifacts and opponents to Muslim rule being harshly persecuted. Even though the Arab forces attempted to force an entirely different culture and traditions on the Iranian people, Iranian culture and the Persian language remained largely intact.
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.