The Ottoman Empire in the 17th century is a land of many contrasts. I know that sounds like the opening to a bad high school essay, but it’s not wrong. The 17th century ended with the Ottomans signing the first disadvantageous treaty they’d ever signed, and while reports of Ottoman decline in this period are greatly exaggerated, I think it’s fair to say that this was a sign of relative, if not absolute, Ottoman decline. In other words, their enemies were catching up to them. On the other hand, the mid-century (1645-1669) Cretan War, or the Fifth Ottoman-Venetian War if you prefer, brought the empire to its largest territorial extent, even if you have to fudge a little to get there (Constantinople/Istanbul didn’t have a whole lot of day-to-day control over, say, Algeria in this period, but Algeria is still considered part of the empire). The siege we’re talking about today was the centerpiece of that war and, as it so happens, one of the longest sieges in recorded history at a whopping 21 years and almost five months.
The Cretan War was fought over, yes, that’s right, Crete, which had been, as the Kingdom of Candia, part of Venice’s maritime empire since 1205, after Fourth Crusade leader Boniface of Montferrat sold the Byzantine Empire’s claim on the island to Venice (he made the sale in 1205, but it took Venice about a decade to secure the island from their Italian rivals, Genoa). Granted, the Byzantine Empire’s claim to Crete wasn’t exactly Boniface’s to sell, but it’s no use crying over spilt milk, right? The point is that Venice owned the island, and the Ottomans coveted it. It was the next big Mediterranean island moving west from Cyprus, which the Ottomans had captured from Venice in 1571, and it also happened to be Venice’s last big island possession, so for both of those reasons it was the natural next target in the empire’s Mediterranean plans.
The Ottomans and Venetians were at peace, and had been since the Fourth Ottoman-Venetian War (the one that included the Battle of Lepanto) ended in 1573. But in 1644 the Knights of Malta attacked an Ottoman fleet in the eastern Mediterranean carrying a few high Ottoman officials and a number of people making pilgrimage to Mecca–the high officials were mostly killed and many of the passengers were taken as slaves. The pirates made for Crete, and depending on which side’s version of events you believe they either stayed there for several weeks and bestowed part of their loot upon the Venetian governor or they had barely landed–without permission–before the Venetian authorities forced them to be on their way. Obviously either story can be seen as self-serving, but clearly the Ottomans believed the former and weren’t persuaded otherwise. However, it does seem that the Venetians were caught off guard when the punitive, ~50,000 man strong Ottoman invasion force arrived at Crete in late June, 1645, rather than continuing on to Malta.
The Venetians had several problems. One, they were vastly outnumbered and couldn’t possibly hope to defend the island with a force comparable to the one the Ottomans brought ashore–Venice was not a large state, and the Thirty Years’ War, which ended in 1648, meant that the rest of Europe was unable to offer much assistance. Two, they weren’t especially popular among the Greek Cretans, and this is ultimately why the Ottomans were able to sustain a 21+ year long siege on an island some distance from the imperial center at a time when, as we’ll see, the Ottomans had little ability to send new supplies by sea–they easily controlled the countryside surrounding the major Venetian cities, and the locals kept them well-supplied. An outbreak of plague, which we’ll come back to at the end of this piece, in the winter of 1646-1647 hit everybody on the island hard but appears to have made it easier for the Ottomans to consolidate control over the rest of the island and prepare to besiege the capital, Candia (modern Heraklion), which they did starting in May 1648.
The Ottomans tried but repeatedly failed to break down Candia’s walls, so instead they tried to choke the city off from its water supply, on land, and from Venice, at sea. Venice couldn’t counterattack the Ottomans on land, but they were still a naval power, and so they attempted to block up the Dardanelles to prevent the Ottoman fleet from resupplying the forces on Crete. This tactic worked very effectively for several years, and a series of engagements in the mid 1650s went Venice’s way and the straits remained blocked to Ottoman traffic. This not only affected the army on Crete, which couldn’t do much beyond sitting there and surrounding Candia without supplies and reinforcements, but also began to adversely affect life in Constantinople. The appointment of a new Grand Vizier, Köprülü Mehmed Pasha (d. 1661), in 1656 turned this situation around. Köprülü enlarged the Ottoman fleet considerably, and this newly empowered fleet removed all traces of Venetian presence from the Dardanelles by the end of 1657.
Candia continued to hold out, in part because Ottoman attention was elsewhere. But the conclusion of the Peace of Vasvár in 1664, ending the 1663-1664 Ottoman-Habsburg War, hastened Candia’s fall by allowing the Ottomans to shift more resources toward ending the siege. A new army, under Köprülü’s direct command, arrived on Crete in late 1666, but even at this the siege took over two more years to conclude, at the cost of tens of thousands more lives–mostly among the Ottomans, who lost far more men overall during the course of the siege than did the Venetian defenders. But the Ottomans simply refused to lift the siege, and Candia was losing its ability to hold out. The defeat of a French relief force that arrived on the island in mid-summer was the last straw for the defenders, who had fewer than 5000 men in fighting condition left at their disposal, and so they surrendered in exchange for safe passage off the island and continued Venetian possession of several smaller islands near Crete and in the Aegean, where Venetian ships could stop on their way east.
While all this was going on, the Venetians were actually winning on the war’s second front, in Dalmatia (part of modern Croatia). The Ottomans were at a logistical disadvantage trying to defend this territory, so hard to get to from Constantinople but so easily accessible to Venice. Anyway, Crete was the prize, and the Ottomans were happy to trade territory in Dalmatia for control over the island. Crete remained part of the Ottoman Empire until 1897, when an uprising (one of a number of 19th century uprisings on the island, whose people wanted to be part of the newly independent Greece) caused the intervention of the European powers and the creation of an independent Cretan state under Ottoman jurisdiction. Crete finally declared its union with Greece in 1908, but that union wasn’t formally recognized until 1913, as part of the Ottoman defeat in the First Balkan War.
I said I’d come back to the plague outbreak at the end of this piece, and the reason is that, fairly recently, research in the Venetian archives has uncovered evidence of a plan, never implemented, for the defenders of Candia to employ biological warfare against the Ottomans. The plan called for a liquid to be made from the spleens and buboes (I know, sorry) of dead plague victims that would then be used against Ottoman camps all over the island. It’s unlikely that this plan would’ve succeeded–the plague bacteria probably wouldn’t have survived long enough–but the Venetians had no reason to know that, and it’s not clear why they wound up not going ahead with the plan. Germ warfare and the bubonic plague have a long history together–it’s believed, for example, that the Mongols hurled plague-riddled corpses into the Crimean city of Kaffa (modern Feodosia) in the mid-1340s and that this ultimately led to the Black Death, although there is research suggesting that Kaffa’s connection to the Black Death may be somewhat overblown.