Battle of al-Firad (12 AH)

Al-Firad lies on the frontiers of Syria, Iraq and al-Jazira. There in 12 AH Khalid ibn al-Walid (may God be pleased with him) met a host of Byzantines, Persian frontier garrisons, and the tribes of Taghlib, Iyad and al-Nimr. They offered him the choice of crossing, and he said, "Cross below us." They crossed and fought a great battle in which the Byzantines and those with them were routed. Khalid ordered the Muslims not to ease the pursuit; a hundred thousand were killed in the battle and the pursuit, according to reports. He remained there ten days, then returned to al-Hira five days before the end of Dhu al-Qa'da. He left it secretly on the pilgrimage and had his head shaved together with the commander of the rear guard. Abu Bakr did not learn of it until after his return, and then rebuked him. In the time of Ali the people of Iraq took pride in it, saying, "We are the people of Dhat al-Salasil," and they would name the stretch between it and al-Firad, without mentioning what came after. ¹.