Islam came to near annihilation in the Thirteenth Century as Franks and Mongols unified and took the Islamist capitals, Baghdad and Damascus. A little known episode. At the time, the overall Mongol Khan was a woman (another little known episode!) But she didn’t cause the problem. Instead Saint Louis’ jealous racism, and unbounded hatred of “infidels” made the difference.
Richard the Lionheart lived in France, where he was supposedly vassal to the king of France, Philip II Augustus his companion in arms (who left the so-called “Holy land” after a while, leaving his soul mate Richard, in charge). Richard may not have lost major battles. But, a century later, Saint Louis, Louis IX of France, did, and ruined France in the process.
It became clear nothing good was achieved by all this crusading. On top of that, the climate started to wobble. Instead, the French switched to the trading model with Islam (rendered possible by treaties consecutive to the Crusades). Immense fortunes were made (Jacques Coeur, born a commoner, became the richest man in France by trading with the Levant in the fifteenth century, and soon, master of the mint, and a most important European diplomat).
Arab chroniclers used the correct term, “Franki” (Franks) to qualify the Europeans trying to (re)conquer the Middle East from the religion of Islam, which had smothered it.
By the time the Crusades were launched, direct Muslim aggression against Europe has been continuous since 715 CE, a full four centuries (the word “Europe” was used first by the Franks in the context of the Muslim invasions). This continual Muslim attack was viewed, correctly, by all concerned, as the continuation of the war of Islam against Rome. (Naturally so, as the Franks so themselves as “Rome”. By 800 CE, the Franks had officially “renovated”, as they put it, the Roman empire…)

Painted in 1337 CE. Notice that the Franks are covered in armor, and the Muslims are not. Obvious technological superiority. The Romans already bought light steel helmets in Gaul! Muslim tech superiority is a lie. In plain view.
There is plenty of evidence that the Franks were more advanced than the Muslims in crucial military technology, as early as 715 CE. How could they not be? The Muslims were just coming out of savage Arabia, all the technology they had, was stolen, or, let’s say, adopted from others.

Four terracotta hand grenades, with “Greek Fire” inside, used by the defenders of Constantinople against the Turks. Greek Fire had many variants, some secret to this day. The Chinese developed dry versions, with salpeter, which turned into black powder later.
The Franks, who had been the crack troops of the Roman empire, as early as 311 CE, had better steel, better armor, better steel weapons, and giant war horses capable of wearing armor themselves. That’s why the Franks were able to defeat the Muslims, overall, in the first phase of the war with Islam, which was in Europe (711 CE, attack on Spain, until the counterattack on Jerusalem, 1099 CE).
This European technological superiority was obvious during the Spanish reconquista. An armored Spanish horse was like an intelligent, indomitable battle tank, which would charge again and again, rarely seriously wounded. By contrast, Muslim cavaliers wore little armor, their relatively small Arab horses were excellent but all too little (I used to ride my own very combative Arab stallion in Africa, which nobody else would, or could, ride… Its name, appropriately chosen, was Napoleon…).
Horse archers were not effective against heavily armored cavalry. They could bother it, but not defeat it. This is why the Mongols decided wisely not to attack the Franks again, after invading, suffering huge losses, Hungary, and Croatia. The Mongols debated what had happened to their ancestors the Huns, eight centuries earlier, in France (annihilation spared only political decision). The Mongols used rocket artillery.
Noah Smith wrote “Why Did Europe Lose the Crusades?“. Said he: “A little while ago, I started to wonder about a historical question: Why did Europe lose the Crusades? The conventional wisdom, at least as I’ve always understood it, is that Europe was simply weaker and less advanced than the Islamic Middle Eastern powers defending the Holy Land. Movies about the Crusades tend to feature the Islamic armies deploying fearsome weapons – titanic trebuchets, or even gunpowder. This is consistent with the broad historical narrative of a civilizational “reversal of fortunes” – the notion that Islamic civilization was much more highly advanced than Europe in the Middle Ages. Also, there’s the obvious fact that the Middle East is pretty far from France, Germany, and England, leading to the obvious suspicion that the Middle East was just too far away for medieval power projection.
Anyway, I decided to answer this question by…reading stuff about the Crusades. I read all the Wikipedia pages for the various crusades, and then read a book – Thomas Asbridge’s “The Crusades: The Authoritative History of the War for the Holy Land“. Given that even these basic histories contain tons of uncertainty, we’ll never really know why the Crusades turned out the way they did. But after reading up a bit, here are my takes on the main candidate explanations for why Europe ultimately lost.”
He pursue by fingering “lack of motivation” as the main cause of the loss of the Crusades. That is true, in part: Europe opened to the ocean. However, the Crusades won in important ways (opening up trade). But the Europeans also really lost, when it would have been easy to win.
Noah Smith’s analysis focuses only on the English (so to speak) aspect of the Crusades. He does not quite say that a rogue frankish army seized Constantinople in 1204 CE. And then he omits completely what happened in the Thirteenth Century (because Richard Lionhearted was then dead, and history is all about the Anglois?).
For politically correct reasons, some of them ten centuries old, some more voguish, allegations have been made of the superiority of Islam (or China, for that matter). These (often self-serving from racist self-declared anti-racists) assertions are not grounded in fact.
By 1000 CE, the Franks had the highest GDP per capita in the world, and its history. European technology was, overall, the most advanced. Europeans were stunned by how little the Chinese used machines and animals.
The Arabic numbers were Greek numbers perfected in India, where the full zero was invented, and were reintroduced through central Asia. Out of the 160 major work of Antiquity we have, 150 survived in European monasteries, the universities of the time (and the ten remaining were saved by the Persians, initially).
The Middle East, long the cradle of most invention, has been clearly a shadow of its former self, ever since Islam established its dictator, intolerance and war friendly terrorizing culture of god obsession.

Crusades in the Middle east until 1204; The image Noah Smith uses, which misinforms the reality of what happened…
Europe didn’t “lose the Crusades”. Saint Louis did. Europe didn’t just decide the Middle East was hopeless, in all sorts of ways. Europe had got reopening of the Silk Roads from Saladin. Meanwhile in 1244, the Khwarezmians, recently pushed out by the advance of the Mongols, took Jerusalem on their way to ally with the Egyptian Mamluks. Europe shrugged (by then “Roman” emperors such as Frederick I Barbarossa had used a Muslim company of bodyguards… So there was strictly no anti-Muslim hatred and racism… contrarily to what happened with the Mongols, see below…)
It is also true that Saint Louis, a weird mix of a dangerous religious fanatic of the worst type, and a modern, enlightened king, lost its entire army (to a woman, the only female leader Islam ever had!) in Egypt. Saint Louis was taken captive at the Battle of Fariskur where his army was annihilated. He nearly died, was saved from dysentery by an Arab physician (impressed Arabs offered for him to rule them). A huge ransom had to be paid, comparable to the French budget. Then Saint Louis died in front of Tunis, in another ridiculous crusade (1270 CE). Louis fell ill with dysentery, and was cured by an Arab physician
Saint Louis, a racist, was the direct cause of the survival of Islam. The Mongols, allied to local Franks had destroyed Baghdad (siege of the Abbasid Caliphate) and Damascus (siege of the Umayyad). The Mongols asked respectfully to make an official alliance with Christianity, and eradicate Islam.
Instead the Pope called Nestorian Christian Mongols heathens, and him and Saint Louis promised excommunication to all and any Frank joining the Mongols in war. Thus the Mongols attacked Egypt without Frankish help, and were defeated by the Mamluks Turks.
Dejected, the Mongols decided that they were Muslims (Islam has no pope, and the Caliphate had been destroyed by the Franco-Mongol alliance ) Under Timor Lame, they would carve a giant Mongol-Muslim empire all the way into India.

This is just a fraction of the common operations of the Franks and Mongols, when they were allied against the Muslims, destroying Baghdad, seizing Damascus. Saint Louis and his pet the Pope saved Islam by calling a halt to the cooperation. Mongols and Franks actually took Damascus together, and the commanders entered the conquered city, side by side…
The Spanish were more serious. They, Isabella, Ferdinand and their advisers, planned to pursue the reconquista by extirpating Islam from North Africa and the Middle East.
The extremely well-trained, battle hardened army was prepared, but then the Americas had just been discovered, and war with France for the control of the world in general and Italy in particular, became everything. Spain engaged in a war with France it took nearly two centuries to lose. The conquest of the Americas changed the world, though. The reconquest of the Christian empire from the Muslims was given up…
It could have been done: the Spanish occupied many cities of North Africa, including Algiers and Oran. Power was divided between Ottoman pirates (“Barbarossas”) and the kingdom of Tlemcen. In any case, in 1525 CE, while Cortez was conquering Central America, defeating among others, the Aztecs, pirates retook Algiers in the name of the Turk Selim 1. At the same time, Selim defeated the Egyptian Mamluks, taking control of the Levant, Mecca, and Egypt.
Islam, a pretty deleterious religion in its literal, Salafist form, survived. North Africa and the Middle East, previously long the world’s wealthiest place, is now the poorest and most war-ridden…
And the war goes on, the ideology of Salafist, literal Islam, being fundamentally antagonistic to civilization.
For the USA, the Iraq war has been an enormous victory: it boosted the price of oil for a decade, enabling the massive deployment of US fracking. Now the USA is again the world’s number one fossil fuel producer. Also French and US military forces are fighting from Mali to Afghanistan, maintaining economic and military control over an area still crucial for energy production (although it will soon become economically irrelevant, from renewable energy).
All the regimes from Mali to Afghanistan, are, officially, friendly to civilization. So why does the war goes on? Because the ideology is islam is centered on Jihad, no holds barred. Thus Islam gives a ready ideology to those who want to make no holds barred. This is why the Turks converted to islam. Within a generation, they had invaded a huge swathe of Central Asia, and overran very old civilization: Georgia, Armenia, and the Oriental Romans (“Constantinople”).
Then Christian pilgrims going to Jerusalem were massacred (up to 10,000 at one time) by various Muslim potentates. Constantinople, having lost half of its territory, to the recently converted, ferociously invading Turks, asked the “Occidental” Roman empire to come to the rescue.
In 1095 Pope Urban II called for the First Crusade in a sermon at the Council of Clermont. He encouraged military intervention for the so-called Byzantine Empire and its Emperor, Alexios I, who needed desperately to stop the westward invasion of the migrating Turks colonising Anatolia.
Morality of all this? What people think they know about history has little to do with what really happened. The forces presently in conflict have been in conflict ever since Islam exists, as Muhammad wanted it. The Quraish, in Mecca, the dominant tribe Muhammad belonged to, didn’t trust Muhammad: he was an analphabet and an epileptic. To boot, Muhammad succeeded in life by marrying a wealthy business woman, and then switching from caravan trading, to caravan raiding.
Just before he died, Muhammad led the first attack against the Romans (who had not attacked him, and refused combat). War is the great arbiter of human destiny. The enormous Roman field army, horrendously led erroneously, was annihilated on its third day of battle at Yarmouk against the Arab Muslim army. Emperor Heraclius, a great general had not been present, he was in Alexandria.
War is a great arbiter, but it is also extremely fickle. Crucial battles are won, and lost, which should never have been won, or lost. Sometimes by sheer happenstance, sometimes from hubris, sometimes by having top generals with top armies not considering the worst imaginable case (as happened to the Romans when fighting the Arabs at Yarmouk, or with Yamamoto at Midway, or the French mid May 1940…).
To learn from history, it has to be learned in full. Civilization missed a chance to eliminate the Islamist war ideology when it aborted the natural alliance with the Mongols. But it’s not very surprising: the overall leader of Europe, then, was Saint Louis. Saint Louis invented the modern justice system, and put his mother, Blanche de castille, in charge of France for many years. So he could be viewed as non-sexist and all for justice. He is represented to this day, rendering justice below an oak. However, Saint Louis was also a savage. He really believed that unbelievers should be killed painfully. Interestingly, Saint Louis came to believe that the Muslims were believers: his fanatical rage was oriented towards Jews and those who, in Christendom, did not believe. So it’s entirely natural that, by considering the Mongols heathens, and forbidding a further alliance with them, he would, in the end, save Islam!
It’s not just that Saint Louis burned 12,000 Jewish manuscripts in Paris, in 1243 CE (5 years before he led the disastrous Seventh Crusade). Saint Louis wrote abominable descriptions of the atrocious ways in which he would kill infidels (I read it in the original texts long ago; however, I was unable to find a source today…)
We have Jihadists around, ready to kill the innocent nowadays, because Saint Louis was actually one of them!
Patrice Ayme’