After the
battle of Kaskar, Numan was appointed the administrator of the Kaskar district. An-Numan was unhappy with the civil appointment and wrote to the caliph
Umar ibn al-Khattab (r. 634–644) requesting active service. In the campaign against the Persians concentrated at Nihawand, Umar appointed An-Numan as the commander of the Muslim army. Before the
battle of Nahavand broke out, Nu'man prayed, "O Allah, grant Nu'man martyrdom with the victory of the Muslims." His prayer was answered where he was martyred first and then the Muslim army won the battle. At Nahāvand, an estimated 30,000 Arab warriors under the command of Nuʿmān attacked a Sāsānian army reportedly of ca. 100,000 men. According to the history writer Peter Crawford, the forces that gathered there was variously recorded as anything from 50,000 to 100,000. Mostly farmers and villagers, not veteran soldiers. After heavy casualties were incurred on both sides, the Persians were defeated. == Death ==