Byzantine Emperors and their relatives met many violent deaths; the favored ways of getting someone out of the way were poison, strangling, and blinding. The last one was the fate of the Emperor who had married his sister to Conrad of Tyre. By 1195, he had presided over many military losses, from the early ravages of German Third Crusaders to defeats in Bulgaria. The Emperor’s brother Alexios took over with the army’s support, and Isaac himself was arrested and blinded. He spent eight years in prison, but survived to have a short second act as Emperor.
Isaac’s son was also called Alexios. He was arrested with his father; however, he not only survived but escaped. Isaac’s daughter Irene had been married off to the King of Germany, who exerted himself to get his father-in-law and/or brother-in-law out of the dungeon. Some Italian merchants smuggled Alexios out of the dungeon and the city, bringing him to Swabia (southern Germany) in 1201. A year later, Prince Alexios met Boniface of Montferrat, a leader of the Fourth Crusade. What Boniface told Alexios interested him very much.
There had already been a Part A of a Fourth Crusade. Remember the German Emperor who had drowned in a river when his horse slipped on a rock at the start of the Third Crusade. His son, Henry VI, was the German king who held Richard the Lion-Heart for ransom, releasing him in 1194 on the payment of 150,000 silver marks. Probably using some of that ransom money, in 1197 Henry VI set out with a German army to Syria, where he took back Beirut and Sidon. The German crusade ended suddenly when Henry VI died along the way; his men fled to Tyre and made their way home. So far so good.
Pope Innocent III was the youngest Pope in many years when he succeeded to the Throne of Peter in 1198. He was energetic and ambitious; he wanted to lead a Crusade himself. Although this didn’t work out, he was able to motivate a group of European noblemen to cobble together a Crusade at a tournament. The English and French kings were at war; the English were often at war among themselves, leading up to the barons’ forcing King John to sign the Magna Carta in 1215. They had no spare funds for an idealistic military venture. The counts and knights who decided to put something together anyway didn’t turn out to have enough money, either. And that was the whole problem.
Earlier Crusades had gone overland through Hungary and Turkey; this was always very dangerous and now that the Crusaders only held a few port cities, it made much more sense to go by sea. A sea approach also allowed them to attack the port cities of Egypt, too. The Counts of Blois, Burgundy, Champagne and Montferrat began by negotiating with the Doge of Venice for a fleet of ships. They settled on a price for transporting about 34,000 men and 4000 horses. In order to meet their obligations, Venice shut down most ordinary commercial shipping and building.
Some of the knights made their own arrangements and came through other ports, but the majority of the men assembled in Venice (I should hope they camped on the shore, not on the sinking islands) in May 1202. They booked passage to Egypt, with the Pope’s blessing. Innocent III made them all vow to do precisely what they were supposed to do and nothing else, including not attacking any Christian cities.
BUT….the Crusaders ran into a problem faced by many people who have planned festivals and conventions: they had way overbooked, considering the number of men who actually showed up. Venice had spent a year readying ships that the Crusaders could not fill, and the Doge expected to be paid for them. They simply did not have enough money, and there was no refund policy. Just like that, the Fourth Crusade was in debt. Paying Venice everything they had set aside for the actual war, it was still not enough. The Doge threatened to hold their leaders under arrest until the total was paid. Then he had an idea.
Putting the Crusade on hold, he suggested that they just do a little mercenary work for Venice. Along the eastern side of the Adriatic Sea, there were many cities that used to pay tax to Venice but had broken away to Croatia or Hungary. The European army could restore Venice’s tax base by shaking down the Adriatic coast. They did this, and eventually had to settle in to besiege the town of Zara. It was a Roman Catholic city and Hungary’s king was also Roman Catholic, so it was off limits for Crusading. But they reasoned that they were simply acting as debt collectors to pay their passage; the real Crusade hadn’t started yet, you see. That’s when Count Boniface of Montferrat decided to make a short jaunt north to see his cousin the King of Germany. He was probably looking for donations, but he found Prince Alexios.
Boniface had a big idea: the Fourth Crusade could back off on the Adriatic towns and re-install Prince Alexios in Constantinople. Alexios was happy to promise them very large payments. True, Constantinople was a Christian city, but it wasn’t a Roman-ruled one, so they suggested to Pope Innocent III that they could also use a conquest to reunite the Eastern and Western churches under Rome. The Pope was not thrilled, but he had worn out his excommunication fury after Zara. The Doge of Venice loved the plan and was happy to use his fleet to transport them. The Crusade leaders were taken aback; their men had vowed to go to Jerusalem. But the Doge’s pressure convinced most of them to sign on, although some went home.