Battle of Siffin

BelligerentsRashidun CaliphateUmayyadSyriaCommanders and leadersStrength 100,000–150,000 men 130,000–150,000 menCasualties and losses 25,000 killed 45,000 killed

The Battle of Siffin (Arabic: معركة صفّين, romanized: Maʿraka Ṣiffīn) was fought in 657 CE (37 AH) between the forces of the fourth Rashidun caliph Ali ibn Abi Talib and the forces of the Umayyad governor of Syria, Mu'awiya ibn Abi Sufyan. The battle is named after its location Siffin on the banks of the Euphrates river. The fighting stopped after Mu'awiya's Syrian army called for arbitration when Ali's Iraqi army started to gain the upper hand, to which Ali reluctantly agreed under pressure from some of his troops. The arbitration process ended inconclusively in 658 though it strengthened the Syrians' support for Mu'awiya and his political position while weakening the authority of Ali and causing dissension among the Iraqis. The battle was part of the First Fitna and is considered a major step towards the establishment of the Umayyad Caliphate.