Daily Quiz for April 4, 2012

The Battle of Oxus River, fought in 644 AD in modern day Turkmenistan. A muslim army of the Rashidun Caliphate led by Ahnaf ibn Qais thoroughly defeated Yazdegerd III, emperor of the Sassanid Empire. Yazdegerd III fled to China. He did not raise an army thereafter, and Iran (Persia) has been an Islamic state since that time.