In 632 CE, when Muhammad died, the entire Muslim community controlled less territory than modern-day Jordan and had perhaps 30,000–40,000 fighting men. Exactly 100 years later, in 732 CE, Muslim armies stood simultaneously at the gates of Constantinople, at Poitiers in central France, and on the banks of the Indus River.

They had annihilated two millennial superpowers — the Eastern Roman (Byzantine) Empire and the Sassanian Persian Empire — and built the largest empire the world had ever seen, stretching 7,000 miles from the Atlantic to the borders of China.

No conquest in recorded history comes close in speed and scale.

Rome took 500 years to dominate the Mediterranean. Alexander’s empire lasted 10 years and then fractured. The Mongols needed 80 years and the greatest cavalry army ever assembled.

The Arabs did it in one lifetime with camels, sandals, and a population that was poorer, smaller, and technologically inferior to both enemies.

Historians still argue about how it was possible. Here is the consensus explanation — and the part that remains genuinely mysterious.

The Setup: Two Exhausted Giants

EmpireCondition in 620 CEFatal WeaknessByzantineJust finished 26-year death-struggle with Persia (602–628) — longest and bloodiest war in Roman historyTreasury empty, army decimated, plague, taxes crushingSassanian PersiaSame war, but lost even more heavily; emperor murdered, civil war for 5 yearsComplete political collapse, no central authority

Both empires were bankrupt, depopulated by plague (Justinian plague 541–549, then recurring), and hated by their own subjects because of religious persecution and crushing taxation.

They were hollow shells waiting to be kicked in.

The Arab Advantages Everyone Lists

1. Religious motivation & unity of command “Paradise lies under the shade of swords” + no separation between church and state = total war with zero dissent.
2. Simple, mobile warfare Camels + light armor = 50–100 miles a day across deserts that Byzantine/Persian heavy cavalry could not cross.
3. Brilliant early generals Khalid ibn al-Walid (“The Sword of God”) — undefeated in over 100 battles, Hannibal-level tactical genius.
4. Treacherous terrain favored defenders — except the Arabs were the defenders in the desert approaches.
5. Tax incentive for conquered peoples Non-Muslims paid jizya but were exempt from military service and often paid less than Byzantine/Persian taxes. Many welcomed the Arabs.

These are real, but they are not enough. Rome had religious motivation. The Mongols had mobility and genius generals. Others offered light taxation. None achieved a 100-year explosion like this.

The True X-Factor: The Ishmaelite Covenant Theology as Superweapon

The conquests were not just military. They were theological fulfillment.

Every victory was interpreted — and experienced — as living proof that God had finally kept His promise to Abraham’s forgotten son Ishmael. The psychological effect was apocalyptic:

1. For the Arab warriors: they were not raiding for loot; they were reclaiming their birthright promised 2,500 years earlier. Defeat was literally impossible because scripture said the land belonged to them.
2. For the conquered populations: when cities fell in days instead of years, when Khalid’s tiny armies shattered imperial legions, many Christians and Jews saw it as divine punishment on corrupt empires and switched sides.

The Arabs fought with the certainty of men who believed history itself was on their side.

No army in antiquity — not even the early Christians — ever possessed a narrative this powerful.

Timeline of the Unbelievable

1. 632: Muhammad dies; Ridda Wars reunify Arabia in 18 months
2. 636: Battle of Yarmouk — 20–40,000 Arabs destroy 100,000+ Byzantine army
3. 637: Fall of Jerusalem
4. 642: All Egypt conquered
5. 651: Entire Sassanian Empire erased from the map
6. 711: Invasion of Spain
7. 732: Battle of Tours (Muslims 400 miles south of Paris)

One lifetime. Two superpowers gone. One new civilization ruling half the known world.

The Verdict of Historians

Hugh Kennedy (the leading scholar of the conquests): “No military conquest in history is as successful and as rapid… We still do not really know how they did it.”

The material explanations are necessary but insufficient. The missing variable is ideological: a desert people suddenly convinced, with incandescent certainty, that they were the rightful owners of the entire Middle East — and that God had waited 2,500 years just to prove it.

That belief turned ordinary Bedouins into the most effective conquering force the world has ever seen.