though they were probably earlier-established there than both. The three tribes became closely allied and formed fictitious genealogical links, making them 'brother' tribes. In the period immediately preceding the Muslim conquest of Syria in the 630s, the older-established Lakhm was exceeded in prominence by the Judham and Amila, especially the former, which practically absorbed the tribe. On the eve of the conquest, the Lakhm lived in groups among the Judham in the region extending north of Tabuk through the desert region east of the Arabah Valley and Dead Sea up to the approaches of the Balqa. Part of the Lakhm also lived in southern Palestine, west of the Dead Sea. Early Islamic period The Islamic prophet Muhammad established contacts with clans of the Lakhm, but the tribe largely remained Christian and allied to the Christian Byzantine Empire along with the Judham. Both tribes fought on behalf of the Byzantines against the Muslims at the Battle of Mu'ta in and were targeted, along with other Byzantine-allied Christian Arab tribes, in the Muslim raid on Tabuk in . At least ten men of the Lakhm's Banu al-Dar clan, including the famous Tamim al-Dari, conferred with Muhammad in his capital Medina and converted to Islam. To these men of the Banu al-Dar, Muhammad granted lands in southern Palestine, including Hebron and its surroundings, though these lands were under Byzantine control at the time and the grant only took effect after the Muslim conquest. Another clan of the tribe, the Banu Hadas, also refrained from joining the rest of the Lakhm at Mu'ta, though information about them is sketchy. In general, the bulk of the Lakhm stood with Byzantium. During the Muslim conquest of Syria, Lakhm tribesmen were counted in the ranks of the Arab tribal fighters led by the Ghassanid chief Jabala ibn al-Ayham in the Byzantine army at the Battle of Yarmouk in 636. Groups of the Lakhm were also counted in the Muslims' ranks as well. In the assessment of the historian Fred Donner, pre-existing divisions and rivalries within the Lakhm likely explains the participation of Lakhm tribesmen on both the Byzantine and Muslim sides at Yarmouk. The unclear allegiance of the Lakhm and Judham during the conquest is reflected in Caliph Umar's order to exclude them from shares in the war spoils around 638, which otherwise were to be equally divided among the Arab tribes in the Muslim ranks. Nonetheless,