The battle of Al-Qadisiyah is one of the battles of the Islamic conquest of Faris, which took place on 13 Shaaban 15 AH (16-19 November 636), between Muslims led by Saad bin Abi Waqqas and the Persian Empire led by Rustam Farkhzad in Al-Qadisiyah, which ended with the victory of Muslims and the killing of Rustam. It was one of the most important battles to open Iraq. The battle witnessed an alliance of the Sasanian Emperor Yazdger III with the Byzantine Emperor Hercules, who married the granddaughter of Manang to Yazdger as a symbol of the alliance.