The Battle of Fahl was a major battle in the Muslim conquest of Byzantine Syria fought by the Arab troops of the nascent Islamic caliphate and Byzantine forces at or near Pella (Fahl) and nearby Scythopolis (Beisan), both in the Jordan Valley, in December 634 or January 635. Byzantine troops smarting from their rout by the Muslims at the battle of Ajnadayn or the Yarmuk had regrouped in Pella or Scythopolis and the Muslims pursued them there. The Muslim cavalry faced difficulty traversing over the muddied grounds around Beisan as the Byzantines cut irrigation ditches to flood the area and stave off the Muslim advance. The Muslims ultimately defeated the Byzantines, who are held to have suffered enormous casualties. Pella was subsequently captured, while Beisan and nearby Tiberias capitulated after short sieges by detachments of Muslim troops.