King Louis IX of France (d. 1270, which is a bit of a spoiler), who would later become St. Louis, would probably go somewhere on a list of the 10 greatest Crusaders of all time, particularly if you limit the list to military figures and to the canonical numbered Crusades (so we’re not including the Albigensian Crusade in France, the Baltic Crusades, or the Reconquista in the Iberian Peninsula). He’d be right up there alongside men like Godfrey of Bouillon, the first Christian “King” of Jerusalem (I put king in quotes because he refused the title), and Richard the Lionheart. The thing is, though, that those guys would make the list because they were pretty good at Crusading (Richard for sure, and Godfrey since, well, his Crusade actually succeeded), while Louis IX…let’s say that he’d be on the list more for his enthusiasm than his performance, and for the fact that he had an excellent biographer.
Louis appears to have deeply believed in the Crusades (look, he wasn’t canonized for nothing; this guy was a very devoted Christian) and he wanted to be a successful Crusader, even to the point where he was prepared to lose his French kingdom by going off on Crusade–losing control of your European holdings was always a concern for any noble who made the journey–not once, but twice. He organized and led the Seventh Crusade starting in 1248, which was the first Crusade to fully acknowledge that you couldn’t capture and hold Jerusalem without first conquering Egypt. Louis sailed an army into the Nile delta in 1249, captured the city of Damietta, and sent a letter to the Ayyubid Sultan al-Salih demanding that he convert to Christianity. Then, over the spring of 1250, he bungled a march on Cairo so badly that his army was decisively defeated once on the way there and again, even more decisively, during a panicked retreat back to Damietta. Louis was taken captive, and had to be ransomed for about a third of his kingdom’s annual revenue.
Obviously this whole effort was not what you’d call “successful.” The one thing Louis had going for him was that he’d brought along a knight and writer, named Jean de Joinville, as his chronicler and later as a close adviser. Jean’s Life of St. Louis does a lot to burnish Louis’ reputation to later audiences, describing in glowing terms his deep commitment to his faith and his great deeds even in the context of telling us about a military campaign that Louis led to total failure.
The failure of the 1248 Crusade apparently gnawed at Louis, and when the Mamluks (who overthrew the Ayyubids in Egypt in 1250) looked like they were about to drive the Crusaders out of the Holy Land altogether (which, in fact, is what eventually happened) in the 1260s, Louis resolved to lead a new Crusade. He declared his intention to do so in 1267. Unfortunately for Louis, nobody else was too keen on the whole Crusading thing by 1267; even Jean de Joinville passed on the chance to accompany his patron and do some more chronicling. Undaunted, Louis selected as his target: Tunis, which…wait, what?
OK, so here’s what happened: Louis had intended to sail to Acre, one of the last Christian holdings in the Holy Land, and do the typical Crusader thing while trying to regain and rebuild the Christian kingdoms that the Mamluks had recently been bullying around. But he got talked into going to Tunis by his brother, Charles of Anjou (d. 1285), who was at the time (as Charles I) the King of Sicily (which he would later lose) and of Naples. Charles believed that the ruler of Tunis, the Hafsid Muhammad al-Mustansir (d. 1277), who had been a vassal of Sicily but broke away when Charles seized the crown there, had some kind of latent Christian sympathies. He believed that an attack on Tunis would somehow–inexplicably it seems to me–be the nudge Muhammad needed to convert. Then, he argued, with Tunis in hand, somehow Egypt would become vulnerable–even though there’s a hell of a lot of land and/or water between Tunis and Egypt–and, as everybody knew, taking Egypt was the key to taking Jerusalem. This is the 13th century version of the Domino Theory, only even less coherent. Basically, Charles wanted Tunis as a Sicilian vassal again, and he knew how to push his brother’s pious buttons to con him into helping.
The Crusade itself was about as close to a complete disaster as anything you’ll find in the copious list of Crusading disasters. Louis decided that the best time to attack Tunis would be in the middle of the hot, dry North African summer (when the area was experiencing weather that would obviously be second nature to a bunch of knights from, ah, France), and so his fleet landed outside of Tunis in July of 1270 and much of his army promptly fell terribly ill. Louis himself died in August, probably of dysentery, and Charles took overall command of the Crusade while Louis’ son, Philip III, became the new King of France. Charles spent the next couple of months, apart from a few small military clashes, negotiating trade concessions with Muhammad al-Mustansir, and finally lifted the “siege” (which was more like a giant open-air infirmary sitting outside of Tunis’s walls than a real siege) on October 30, when the Hafsid ruler agreed to allow free trade between Europe and Tunis and to protect Christian clergy living in his territories. I’d say the Eighth Crusade ended with a whimper instead of a bang, but to say that it “ended” at all would erroneously imply that it ever really got started.
Louis IX died on Crusade, not in battle but certainly at the “hands” of the Eighth Crusade’s deadliest foe, disease. Charles later became the King of (just) Naples, after the Sicilian Vespers uprising in 1282 drove him off the island and brought it under the control of the Kingdom of Aragon. The (Berber) Hafsids ruled Tunis, along with a fairly large tract of Northern Africa, until 1574, so they did quite well for themselves. As for the Crusades themselves, well, the Ninth Crusade got going right after the Eighth collapsed; in fact, it was led by Prince Edward of England (later King Edward I, or Edward Longshanks for you Braveheart fans), who had negotiated a deal with Charles to land a joint army at Acre in 1271. Charles, his army still reeling from disease and having difficulty making safe passage across the choppy Mediterranean, never showed up. Edward’s small force raided around the countryside and made an alliance with the Mongols, but ultimately it accomplished nothing, largely because there was really nothing left to be accomplished.
There was little enthusiasm for Crusading in Europe anymore, so it was hard to raise a large enough Crusading army to make any real headway, and the rump Crusader state couldn’t contribute much more than a friendly port to the effort (and even that was lost when Acre fell to the Mamluks in 1291). The Eighth-Ninth Crusade (they’re often grouped together since they happened almost simultaneously and were two parts of what was suppose to be a joint effort) was really the end of the line for the Crusading movement; there was a “Tenth Crusade” in 1365 that briefly captured the Egyptian city of Alexandria, but that was really a war between Cyprus and Egypt that got dressed up as a “Crusade” for PR reasons.