To be brief, the answer comes down to numbers: the Crusaders lost, and the Muslims won, ultimately because of numbers—large Muslim numbers against small Christian numbers.
And what caused this imbalance? Simple, unlike the cold logic that fueled history’s Muslim conquests, the Christian desire to take and hold the Holy Land was motivated by purely idealistic reasons, and these ultimately proved too impractical to sustain.
Consider: history’s Muslim conquests were wholly pragmatic and followed the usual model. Muslim armies always targeted whichever “infidel” populations were closest to them. That’s because all non-Muslims were enemies, and their conquest proceeded wherever and whenever it was most convenient for Muslims.
By contrast, the Crusader effort was not aimed at conquering infidels per se, but at securing and holding a specific and highly important piece of real estate: the Holy Land—where Jesus walked, taught, died, and was resurrected.
To better understand all this, let’s take a closer look at how the Muslim conquests of history unfolded.
Beginning from their Arabian homeland, Muslim forces moved outward by subduing their most immediate neighbors. To the northwest lay Christian Syria and Egypt; to the northeast, Zoroastrian Persia. Rather than bypassing these regions in pursuit of distant objectives, Muslims first focused on conquering and fully consolidating these adjacent territories.
Only after Syria, Egypt, and Persia had been secured did Muslim armies proceed further west into North Africa, and further east into Central Asia and India. Each conquest strengthened the next. Regions were not merely occupied but brought into the “House of Islam,” the umma. This sequential, contiguous expansion ensured that Muslim forces always operated with secure lines of communication and an ever-growing base of manpower and resources immediately behind them.
In other words, Muslim armies never flung themselves deep into hostile territory, with enemies surrounding them. Instead, they advanced, step by step, always within easy reach of their own world—friendly populations, supply networks, and reinforcements, as well as defensible territory which they could retreat back to in the event of a setback.
For example, consider the Muslim conquest of Spain. Rather than try to subdue that Christian peninsula prematurely, Muslim forces first spent their energies conquering and consolidating all of North Africa, which for decades put up a stubborn defense, particularly its Berber populations. Only once that region was firmly under Muslim control, and the Berbers Islamized, did the Arabs invade Spain from their nearest African base, Morocco, in 711—some eighty years after the initial conquests of Syria and Egypt.
