Battle of Fahl

32°27′N35°37′E / 32.450°N 35.617°E / 32.450; 35.617

BelligerentsRashidun CaliphateByzantine EmpireCommanders and leadersTheodore Trithyrius (identified in Muslim sources as Saqallar ibn Mithraq)Strength 20,000–30,000 (estimations) 50,000–100,000 (Arab sources)Casualties and losses A few hundreds to a few thousands 100,000 killed

The Battle of Fahl (Arabic: يوم فحل, romanized: Yawm Faḥl), also known as the Battle of the Marshes (Yawm al-Radagha) and the Battle of Beisan (Yawm Baysān), was a major battle in the Muslim conquest of Byzantine Syria fought by the Arab troops of the Rashidun 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 had regrouped in Pella or Scythopolis and the Muslims pursued them there. The Muslim cavalry faced difficulty traversing 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 said to have suffered enormous casualties. Pella was subsequently captured, while Beisan and nearby Tiberias capitulated after short sieges by detachments of Muslim troops.