July 634 · Palestine Theater

In the first great pitched battle between the Arabs and the Byzantine Empire, the Muslim armies converging on Palestine crushed a Byzantine field army at Ajnadayn. The victory, won soon after Khalid ibn al-Walid's legendary desert march from Iraq to Syria, opened Palestine and Syria to conquest.

August 636 · Syria (Yarmouk River) Theater

Heraclius gathered a great army to reverse the Arab conquests, and it met the Muslim host over six days along the ravines of the Yarmouk River. Khalid ibn al-Walid's brilliant use of mobile cavalry, and a dust storm blowing into Byzantine faces, culminated in a Muslim attack that drove the imperial army back against the gorges, where much of it was destroyed.

November 636 · Mesopotamia (Iraq) Theater

On the edge of the Mesopotamian plain, the Arab army under Sa'd ibn Abi Waqqas faced the main Sasanian host with its war elephants and elite savaran cavalry, commanded by the great general Rostam. After several days of ferocious fighting — the Arabs learning to counter the elephants — the Persian line broke, Rostam was killed, and the Sasanian army was destroyed.

April 637 · Palestine Theater

After Yarmouk left Palestine defenceless, the holy city of Jerusalem was besieged and then surrendered on terms. The Patriarch Sophronius insisted on handing over the city only to the Caliph himself, and Umar came from Medina, entering the city humbly and guaranteeing the safety of its Christian inhabitants and their churches in a famous covenant.

641 – 642 · Egypt Theater

The general Amr ibn al-As invaded Egypt with a small army, defeated the Byzantines at Heliopolis, and after a long siege took the great fortress-port of Alexandria, one of the largest cities in the world. Egypt's Coptic Christians, alienated by Byzantine religious persecution, offered little resistance to the conquerors.

642 · Media (western Iran) Theater

The last Sasanian emperor, Yazdegerd III, gathered a final great army in the highlands of Media to halt the Arab advance into the Iranian plateau. At Nahavand the Arabs lured the Persians out of their fortified position and destroyed them, though the Muslim commander al-Nu'man was killed in the moment of victory.

655 · Mediterranean, off the coast of Anatolia Theater

The young Arab navy, built in the conquered ports of Syria and Egypt, met the Byzantine fleet under the Emperor Constans II himself off the southern coast of Anatolia. Lashing their ships together to fight a land battle at sea, the Arabs boarded and overwhelmed the Byzantine ships in a bloody melee, and the emperor barely escaped.

674 – 678 · Constantinople Theater

The Umayyads mounted a years-long blockade of Constantinople, basing their fleet nearby and assaulting the city each campaigning season. But the great walls held, and the Byzantines unveiled a terrifying new weapon — 'Greek Fire,' a liquid incendiary sprayed from their ships that burned even on water and destroyed the Arab fleet.

July 711 · Hispania (southern Spain) Theater

Crossing from Africa at the rock that still bears his name — Gibraltar, Jabal Tariq — the Berber-Arab commander Tariq ibn Ziyad met the army of the Visigothic king Roderic near the Guadalete river. Treachery among the Visigothic nobles and Tariq's determination broke the Gothic army; Roderic vanished, presumed killed, and the Visigothic kingdom collapsed with astonishing speed.

717 – 718 · Constantinople Theater

The Umayyads launched their greatest effort against Constantinople, a vast land and sea assault under Maslama. But the emperor Leo III, the walls, Greek Fire, a brutal winter, Bulgar attacks on the besiegers, and disease and starvation combined to destroy the enormous Arab army and fleet. Only a fraction of the huge host that had set out ever returned.

October 732 · Gaul (Frankish kingdom) Theater

An Umayyad army raiding out of Spain into the heart of Gaul was met between Tours and Poitiers by Charles Martel and his Frankish infantry, drawn up in a dense, disciplined square. For a day the Frankish shield-wall held against the Muslim cavalry charges; the Umayyad commander Abdul Rahman was killed, and the Arabs withdrew in the night.

July 751 · Central Asia (Talas River) Theater

Far to the east, the expanding Abbasid Caliphate collided with the other great empire of the age — Tang China — at the Talas River in Central Asia. When the Turkic Karluk allies of the Chinese defected to the Arabs during the battle, the Tang army was destroyed, halting Chinese expansion west of the Pamirs.