The Fourth Crusade is arguably the single most stupid multi-lateral policy the West took since the fall of the Western Roman Empire. Although it’s not very well-known (crusades conjure up images of Templars in the Holy Land, although crusades also occurred in Eastern Europe and against the Cathars in France), it had dramatic implications for the short term, and enormous implications in the long term.
For reasons of trade, Venice was not best friends with Byzantium, capital of the Eastern Roman Empire, in the early 13th century. An ever-widening religious gulf between the Western Latin Church and Eastern Orthodox Church meant that there was also a great deal of rivalry within Christendom.
And so, when the Fourth Crusade appeared in financial difficulty, Enrico Dandolo, the ancient, blind Doge of Venice, played a pivotal role. In return for funding, he diverted the Crusade to Byzantium. Not only was this helpful for Venice, Byzantium, despite being on the ropes in the years leading up to the Crusade, was immensely rich. If it fell, there would be enough booty to satisfy every man who partook in the city’s conquest.
Byzantium, at this stage in history, was suffering. The Ottomans were making continual progress in the East, and the glory days of Nicephorus Phocas, John Tzimisces, Basil II, and Alexius and John Comnenus seemed very long ago. The ironically entitled Angeli dynasty had been steadily buggering the Empire’s fortunes through a combination of stupidity and ill fortune.
By contrast, Dandolo was a brilliant, persuasive, energetic man, despite his advanced years (he was over 90 at the time of the Fourth Crusade). Under his leadership, the Fourth Crusade did what no-one else (until the advent of gunpowder) ever managed. Byzantium, despite its invincible land walls, was conquered.
The leadership of the city fled to establish an empire-in-exile, occupying what remained of Roman territory in Anatolia (modern day Turkey). Meanwhile, the Latin potentates and Dandolo plundered the city and carved up the rest of the Empire between themselves.
It was a great success, especially for Venice. Or so it seemed.
In time, the Latin leaders set to squabbling. They didn’t understand the culture or religion of the land they were trying to govern, and their less than subtle approach did not universally endear them to the Byzantines. The empire-in-exile reclaimed the city. But it took several decades, and came at great cost.
During this time, the Turks did not sit about. They, naturally, took advantage of the situation to advance. The greatest (indeed, only) bulwark against their expansion from the east had been Byzantium, and the Empire, which rapidly diminished to a mere city-state, never recovered even a shadow of its former power. The Fourth Crusade had shattered Byzantium, and the next two and a half centuries were a lingering death.
When Byzantium truly fell, in the mid-15th century, it was not to the advantage of the Latin Church or Venice. Precious little help was given to defend the city (although a few men did heed the desperate plea). After it fell, the Ottoman expansion continued for centuries, halting only at the gates of Vienna in 1683.
As I mentioned, Byzantium had been on the ropes even before the Crusade. But it’s also worth noting that it had had dodgy moments and recovered before (between Basil II and Alexius Comnenus were many years and numerous unimpressive emperors). After the Fourth Crusade, it was in perpetual decline. And not because the Ottomans had struck a decisive blow. But because the Fourth Crusade had done so on their behalf.
Thank goodness we don’t make short-sighted decisions for narrow-minded self-interest any more.