Our “Today in History” posts are always free, but if you want to support the newsletter and get the full Foreign Exchanges experience you know what you have to do:
If it's fair to say that the Fourth Crusade's sacking of Constantinople discredited the whole enterprise, and in my opinion it is, the Sixth Crusade wrung the last vestiges of seriousness out of the movement. Ironically, of the numbered Crusades it was one of the more successful—certainly more successful than the disastrous Second, Fifth, Seventh, and Eighth Crusades and the...whatever the Fourth Crusade was. An argument could be made that it was the most successful numbered Crusade other than the First, since like the First Crusade it ended with a Christian (well, sort of Christian) ruler having gained control of Jerusalem. That's how the early Crusaders would've defined "success" and so I think it's impossible to argue that the Sixth Crusade was a failure, at least on paper.
I say "ironically," though, because the outcome of the Sixth Crusade has to be tempered by an amazing number of caveats. For one thing, its leader had been excommunicated (hence my "sort of Christian" remark above), which gives this Crusade the unique distinction of having been actively opposed by the Church. For another thing, it involved barely any actual fighting. It was, instead, a long negotiation between that excommunicated Crusader king—who didn't really want to be on Crusade, didn't really have much of an army with him, and had no support from the Church—and the leaders of an Ayyubid sultanate that was by this point so decrepit that it didn't dare risk going to war even with a guy who didn't have much of an army.
The later Crusades, with the Sixth Crusade ("Frederick II's Crusade") marked in green
The Sixth Crusade was, if you want to be crude about it (and why not?), Holy Roman Emperor Frederick II's (d. 1250) middle finger to Pope Gregory IX (d. 1241). Frederick was undeniably the most powerful European monarch of the period, but he also had this habit of talking about going on Crusade without actually ever going on Crusade. Frederick had promised to take up the cause of the Holy Land at his coronation as King of Germany in 1215, and dramatically renewed his pledge when he was crowned emperor in 1220, but he nevertheless waffled on joining the 1213-1221 Fifth Crusade, which attacked the Ayyubids in Egypt. Throughout that campaign's siege of Damietta and the army's deleterious year of inactivity after finally capturing the city, Frederick kept sending messengers to the Crusaders promising that he was on his way. Some German forces did eventually arrive at Damietta, just in time to join the army's disastrous march south, but Frederick himself, and the vast army he supposedly led, never arrived.
As you might expect, some people took a dim view of Frederick after the Fifth Crusade went bust. Among them was Pope Honorius III (d. 1227), who rebuked Frederick for his inaction by letter in 1221. Relations between Frederick and the Vatican weren't great anyway, which was the norm between popes and Holy Roman Emperors, who were constantly feuding over issues of primacy in the Church. But Frederick's abandonment of the Crusade added a new and powerful grievance to the Pope's side of the argument. The emperor assured that pope that he had wanted to go on Crusade but just hadn't been able to leave Germany, and in his defense he really had been occupied with consolidating his rule over the empire. He promised to lead a great new Crusade that would leave in 1225, ten years after he'd first promised to take up the cross. Then in 1224, he told Honorius that he was going to need more time to put an army together. To fend off a possible excommunication, Frederick assured Honorius that his Crusade would leave in August 1227, and even signed a document that made it clear he would be excommunicated if he failed to leave at that time.
In the meantime, Frederick had been widowed, and his search for a new bride landed on Isabella, the daughter of the titular King of Jerusalem, John of Brienne. Since Jerusalem was back in Muslim hands by this point, the "King of Jerusalem" actually ruled from the city of Acre, but the title was probably more important than the city. John was reluctant to consent to the marriage, fearing that the much more powerful Frederick would claim the throne of Jerusalem by marriage. Honorius, on the other hand, loved this idea because he assumed it would commit Frederick to going on Crusade, finally. Frederick denied that he had any interest in claiming the throne of Jerusalem, and so John consented, and Frederick and Isabella were married in 1225. Frederick then, and you knew this was coming, claimed the throne of Jerusalem.
Frederick marrying Isabella, from the 14th century Nuova Cronica by Italian writer Giovanni Villani (Wikimedia Commons)
So by 1227 Frederick was well motivated, both by his pledge and a desire to legitimize his newly claimed kingship, to go on Crusade. It was also a very good time to attempt a new campaign. The Ayyubids were in the midst of a civil war between the sons of the previous sultan, al-Adil (d. 1218), and Frederick was in talks with one of those sons, al-Kamil, about turning Jerusalem over to the Crusaders in exchange for military aid. The time to head to Jerusalem would never be better. And indeed, Frederick's army set sail in August 1227 as promised. It's just that Frederick, uh, wasn't with it. He'd been stricken by plague and headed to Naples to recuperate, and despite his promises that he was definitely going to head east just as soon as he could to meet up with his army and do that whole Crusade thing, don't you worry, he seemed pretty comfortable staying there (of course, and again in Frederick's defense, he had been quite ill). The new pope, Gregory IX, was uninterested in Frederick's excuses/promises, and excommunicated him in late September.
Frederick finally sailed for Acre in May 1228. The Crusade, now led by an excommunicate, was—in technical religious terms—a gigantic mess. Gregory actually urged Frederick not to go (talk about doing a 180) and then sent letters to Acre warning everyone there that Frederick was not to be obeyed as he was not a legitimate Crusader (nor, at that point, a legitimate Christian). He even excommunicated Frederick a second time, I guess in case the first one hadn't taken or something. But Frederick went anyway. Hence the whole exercise from this point on became that middle finger to the pope I mentioned above. Isabella even died shortly before Frederick left, which technically meant he no longer had any claim to be King of Jerusalem, but he doesn't seem to have cared about this either. I've seen Frederick called an "atheist," and while I'm not sure that's a reasonable statement (in context it seems like a pejorative) it is pretty clear that he wasn't particularly bothered by these sanctions from the pope.
The one development that did affect his plans was that al-Kamil's main rival for the throne, his brother al-Muʾazzam, had by this point died, and so the Ayyubids no longer had any incentive to trade Jerusalem for Frederick's military aid. After arriving in Acre (after yet another lengthy delay in Cyprus hashing out Jerusalem's political situation) and spending some time wrangling with al-Kamil's negotiators, Frederick marched his army to Jaffa to rebuild that city's fortifications, which was intended as a threat to al-Kamil. Frederick's army wasn't nearly the size it had been when it set out—it seems that when they arrived at Acre without their ruler, most of Frederick's men figured that he'd backed out of yet another promise to Crusade and decided to go back home. But this march to Jaffa was impressive enough, apparently, to convince al-Kamil to make a deal.
Frederick (left) meets al-Kamil in this 14th century miniature (Wikimedia Commons)
The deal, which was signed on February 18, 1229, let Frederick claim a technical victory and get the hell out of Dodge, but its terms were laughable. Al-Kamil gave Jerusalem to Frederick, but the city had to be kept unfortified, all Muslims living there had to be allowed to remain, and the city's Muslim holy places would still remain in Muslim hands. In other words, Frederick was given possession of the city in name only. When he heard the terms of the deal, the Patriarch of Jerusalem refused to formally crown Frederick King of Jerusalem in the Church of the Holy Sepulcher, and Frederick's army, largely made up of Templars and Hospitallers, rejected the deal as a paper victory.
Frederick made a brief entry into Jerusalem, where he may have crowned himself (it's not entirely clear), before returning to Acre, where the Patriarch was actually raising his own army to march to Jerusalem and garrison the city properly. This, of course, would have completely wrecked the deal Frederick had cut with al-Kamil, and he therefore put a stop to it. Meanwhile, word reached him that Gregory and John of Brienne were campaigning against his possessions in Italy, so he had to leave. As a final gift to the Crusaders he was leaving behind, Frederick made sure to destroy all their siege engines, so they wouldn't get any funny ideas about marching on Jerusalem once he'd left. As Frederick rode to the harbor to board his ship home, we're told that angry townspeople threw garbage at him.
Frederick recovered his Italian holdings, made peace with John and Gregory, and was restored to the Church in the Treaty of Ceprano in 1230, but Gregory excommunicated him again in 1239 when Frederick attacked and defeated the Vatican-allied Lombard League in northern Italy. He spent most of the rest of his life in a literal state of war with the papacy and was actually excommunicated again by Pope Innocent IV in 1245. Jerusalem, meanwhile, came back into Muslim hands in 1244, following a siege by a Khwarazmian (Central Asian) army that had been recruited for the task by al-Kamil.