Battle of al-Qādisiyyah

The Battle of al-Qādisiyyah (Arabic: معركة القادسيّة‎; transliteration, Ma'rakat al-Qādisiyyah; Persian: نبرد قادسيه‎; alternative spellings: Qadisiyya, Qadisiyyah, Kadisiya), fought in 636, was the decisive engagement between the Arab Muslim army and the Sassanid Persian army during the first period of Muslim expansion. It resulted in the Islamic conquest of Persia and was key to the conquest of Iraq. The battle also saw the alleged alliance of Emperor Yazdegerd III with Byzantine Emperor Heraclius, who married his granddaughter Manyanh to Yazdegerd as a symbol of alliance.

• http://en.wikipedia.org/wiki/Battle of al-Qādisiyyah