Battle of the Yarmuk

The Battle of the Yarmuk (also spelled Yarmouk) was a major battle between the army of the Byzantine Empire and the Arab Muslim forces of the Rashidun Caliphate. The battle consisted of a series of engagements that lasted for six days in August 636, near the Yarmouk River (also called Hieromyces River), along what are now the borders of Syria–Jordan and Syria-Israel, southeast of the Sea of Galilee. The result of the battle was a complete Muslim victory that ended Byzantine rule in Syria. The Battle of the Yarmuk is regarded as one of the most decisive battles in military history, and it marked the first great wave of early Muslim conquests after the death of the Islamic prophet Muhammad, heralding the rapid advance of Islam into the then-Christian Levant. To check the Arab advance and to recover lost territory, Emperor Heraclius had sent a massive expedition to the Levant in May 636. As the Byzantine army approached, the Arabs tactically withdrew from Syria and regrouped all their forces at the Yarmuk plains close to the Arabian Peninsula, where they were reinforced, and defeated the numerically superior Byzantine army. The battle is widely regarded to be Khalid ibn al-Walid's greatest military victory and cemented his reputation as one of the greatest tacticians and cavalry commanders in history. In 610, during the Byzantine–Sasanian War of 602–628, Heraclius became the emperor of the Byzantine Empire, after overthrowing Phocas. Meanwhile, the Sasanian Empire conquered Mesopotamia and in 611 they overran Syria and entered Anatolia, occupying Caesarea Mazaca (now Kayseri, Turkey). In 612, Heraclius managed to expel the Persians from Anatolia but was decisively defeated in 613 when he launched a major offensive in Syria against the Persians. Over the following decade, the Persians were able to conquer Palestine and Egypt. Meanwhile, Heraclius prepared for a counterattack and rebuilt his army. In 622, Heraclius finally launched his offensive.