Tottering empires
The phenomenon most likely to provide the Turks with a casus belli that would justify their invading Crete was Christian piracy, at that time a flourishing business. The Knights Hospitallers of St. John were a military order founded in the Holy Land at the time of the early crusades. When it was finally clear that further attempts to conquer the Holy Land for Christianity would be fruitless, the Knights in their wisdom defined piracy as a continuation of the holy struggle against Islamic power.
Janissaries attacking the Knights of St. John at Rhodes
As pictured in this Turkish miniature, the Knights of St. John were expelled from their stronghold of Rhodes on New Years’ Day, 1523 by the youthful Sultan Suleiman the Magnificent: this was the first of his victories. They transferred their operations westward to the much smaller island of Malta, which the Holy Roman Emperor Charles V, eager to support any resistance to Turkish domination of the Mediterranean, granted them. From there they willingly joined all wars against the Ottomans, but whenever there wasn’t a war going on they continued their policy of freebooting in the name of Christ.
The Turks besiege Malta, 1565 (by Matteo Perez d'Aleccio)
The Sultan sent a major expedition against Malta in 1565, but with assistance from other Western countries it withstood the siege. During the next century, the Venetians were sometimes allied in wartime with the Knights of Malta (as the Knights of St. John were now known), but in general they deplored the knights’ piracy as a threat to peace with the Turks—a peace that Venice was more than ever anxious to keep. Deplore though they might, however, the Venetians couldn’t put a stop to the piracy, which the Knights of Malta insisted was a pious duty. The fear that this behavior might eventually bring about a Turkish attack on Crete is recorded in more than one report sent to Venice by its governors on the island.
16th-century Maltese galley
In 1644, a Turkish convoy carrying several very important persons and their families to Egypt (on their way to Mecca, where they intended to make the pilgrimage called the hajj) encountered six Maltese galleys—all built in Venice, which may or may not be relevant to subsequent events—not far off the Cretan coast. The picture shows a scale model of a 16th-century Maltese galley, probably not much different from those of the 17th, with reefed sails. The postage stamp below, from a series created by the Bulgarian artist Stefan Kanchev, has more charm (if charm can be associated with a pirate ship rowed by prisoners or slaves). The devout pirates defeated the convoy and captured its principal ship, a very large galleon named the Sultana. A prize crew sailed it to an unguarded harbor on the Cretan coast, where they unloaded some Greek slaves and a few horses.
Maltese galley (Bulgarian postage stamp by Stefan Kanchev)
The horses may be fictitious. There was apparently a popular Turkish belief that soil trodden by Muslim horses would ultimately belong to Islam, and the story that the pirates debarked some stolen horses from the captured ship—Turkish ownership apparently being sufficient to make them Muslim horses—was circulated in Istanbul as war fever rose. But the galleon, which had 600 humans aboard, could have carried some horses as well.

The Venetian governor soon showed up and ordered the pirates off, and after a few fruitless attempts to land elsewhere in Crete, they abandoned the galleon and its passengers—presumably in Crete, though the account doesn’t say—and went home to Malta. Another source says that the pirates had killed some of the eminent captives, including the immensely rich chief eunuch of the Sultan’s harem, whose immense riches they divvied up. It seems doubtful that this official would have been carrying his entire fortune with him on the voyage, but as a rich and important Muslim he might have carried a large sum for making charitable offerings, a traditional act of piety for wealthy Muslims on the hajj. This story, at least in part, may be another that sprang up in the hothouse ambience of war fever.
Sultan Ibrahim I (reigned 1640–1648)
The Ottoman ruler at the time was Sultan Ibrahim I, who was emotionally unstable and believed to be mad. In the first years of his reign, all decisions of state were made in his name by the Grand Vizier in cahoots with Ibrahim’s own mother, an ethnic Greek whose original name was Anastasía. But in 1643, the Sultan had suddenly thrown off his passivity, exiled his mother, executed the Grand Vizier, and taken the reins of power into his own hands. A certain amount of chaos ensued. The Sultan came under the influence of a kind of Muslim Rasputin, a religious figure named Jinji Hodja, who was an enthusiastic advocate of war with Venice. It was he who interrogated the Venetian ambassadors about the incident with the Maltese pirates and made the determination that Venice was to blame. Istanbul was soon infected with the war fever mentioned above.

In the spring of 1645 an enormous expedition was organized under the command of the chief admiral, Yusuf Pasha, a warhawk and ally of Jinji Hodja. (Yusuf Pasha’s original name was Josef Masković; he was a Dalmatian convert to Islam.) The Turks encouraged the Venetians to believe that they intended to attack Malta. When the fleet left Istanbul, at the end of April, 1645, it even sailed some distance out of its course to maintain this illusion, successfully keeping the Venetians off their guard.

In spite of the massive fortifications built in Crete during the previous century, the island was in no shape to fend off a full-scale invasion. Its fortresses hadn’t been properly maintained, garrisoned, or supplied, and its landowners had been lackadaisical about their obligation to supply and support a militia. It was a seriously bad moment for the Cretan colony when the Turkish fleet turned in their direction on June 21 and arrived on the northwest coast near Canea (Chaniá) four days later.
Siege of Canea, 1645
Venice hastily dispatched what men, ships, and money were on hand, but they were far from enough. The Republic promised to send another, larger fleet—but ordered it to wait for a rendezvous with allies from Tuscany, Naples, Malta, and the Papal States. This of course ensured that the fleet arrived too late to help. Canea was besieged, and fell, nearly out of food and ammunition, after two months..

The Rough Guide tells of a defense that cost 40,000 Turkish lives, and also cost Yusuf Pasha his head when he took that news to the Sultan, but I can’t find this information confirmed elsewhere. Other accounts say that the Turks granted the city, its residents, and its defenders generous terms in the hope that this might lessen resistance in other parts of the island. That doesn’t sound like something they’d do for people who had just slain 40,000 of their comrades. As for Yusuf Pasha’s unhappy end, it has been attributed to the Sultan’s rage when a Venetian fleet succeeded in blockading the Dardanelles, temporarily preventing the departure of Ottoman reinforcements. Or else it's attributed simply to the perils of Ottoman politics at the time.

The combined fleet arrived at last, too late to prevent the capture of Canea. Its commanders made a couple of attempts by land and sea to retake the city, but these were frustrated. Venice’s allies poked about for a while and then went home; they had never been enthusiastic about the mission. Waiting for them had done the defense more harm than good.

The Turks began taking smaller Venetian strongholds scattered about the island, one at a time. In the autumn of 1646, more than a year after the fall of Canea, they succeeded in taking the next largest city, Retimo (Réthymno), despite its huge Fortezza. The city, which lay outside the walls, surrendered on October 20, and the fortress, which had little left to protect, only three weeks later. The reduction of smaller forts continued until the whole island, except for its strongly fortified capital, Candia, was in Turkish hands.

The siege of Candia itself began in May, 1648. It ended when the Venetian Captain-General, Francesco Morosini, surrendered the keys of the city to the Grand Vizier Ahmed Küprülü in September, 1669—21 years later. (It has been nominated for the honor of being the longest siege in history.)

Sultan Ibrahim didn’t live to see the end of the siege; in fact, it was only in its fourth month when he was strangled at the behest of his Grand Vizier. Ibrahim’s rule had become increasingly bizarre. Besotted with heavy women, he had sent agents throughout the empire to recruit them for his harem. In Georgia they found a woman who weighed 330 pounds and was called by the pet name Şeker Pâre (‘Sugar Lump,’ more or less). She pleased the sultan so well that he awarded her a state pension and the title of Governor General of Damascus. He had also been seen feeding gold coins to the fish in the palace pool. It was obvious that he had to go. (All of this must be true; I found it in Wikipedia.)
Map of Candia and its fortifications
Candia’s defensive bastions held firm against years of Turkish artillery bombardment. The city and its garrison were successfully supplied by sea. Unlike Retimo, Candia was inside the fortifications. It doesn’t seem that the fighting was intense during all that time; both sides apparently resigned themselves to a war of attrition. Venice fought hard at sea, sometimes managing to bottle the Turks up inside the Dardanelles. They sought help on both land and sea from other European powers, and sometimes got it. In general, however, the small forces that came accomplished little, and were disinclined to remain for long. Venice also engaged hired help, including warships from places like Holland, but the victories they won at sea did little to improve the military situation in Crete.
Candia under siege

During the last two or three years of the siege, attrition gave way to what one historian describes as “a frenzy of destruction and bloodletting.” The illustration above, printed on a map published by Nikolaes Visscher of Amsterdam, may be based on a painting from this period. When a French expedition that represented the last possible attempt to relieve the siege failed and departed, Captain-General Francesco Morosini decided that surrender was preferable to slaughter, the only alternative that was realistically foreseeable. The Grand Vizier refused to budge on his demand for the complete surrender of the island, but his terms were otherwise generous. All Venetians, military and civilian (and also upper-class Greek families who had been integrated into Venetian society) were allowed to depart unharmed with as much of their property as they could carry. Venice was allowed to keep three offshore bases, all on small islands: Spinalonga, off Áyios Nikólaos (which is between Candia and Sitía); Souda, a little east of Chaniá; and Gramvoúsa, at the extreme northwest of the island, near the tip of a peninsula with the same name. All had harbors where Venetian merchant ships trading with the East could take shelter, and for several decades Venice also cherished hopes that they might be instrumental in a reconquest of the island. But such hopes were in vain, and in 1715 these three bases were lost along with all Venice’s remaining possessions south and east of the Adriatic. (The Serenissima Republica itself perished less than a century later when, after being occupied by Napoleon, its territory was divided between France and Austria in a 1796 peace treaty.)
Polish hussars charging the Turks at Vienna, 1683
Crete was the last substantial conquest of the Ottoman Empire. It had reached its maximum size and from now on would only lose ground. The Turks made a final attempt on Vienna in 1683 that reached and set siege to the city, but they not only failed to take it; they were roundly defeated by a Polish army that arrived to relieve the siege. (This picture of Polish hussars charging the Ottoman besiegers is an obvious product of patriotic imagination, but the victory was genuine.)

From that time on on Turkish military power was unmistakably declining in comparison to that of major European states. One possible cause was increasing religious and political conservatism in Ottoman society, related to the growth of a network of interest groups inclined to dispute issues of wealth and power with the sultanate. This kind of disharmony tended to impede the empire’s previous willingness to learn and adopt new military techniques and technologies. And as the West went on expanding its oceanic trade—and, through colonization, exploiting the resources not only of the Far East but also of the newly discovered Americas—the Ottomans, like the Venetians, fell behind most of Europe economically as well as militarily.
Powers picking up pieces of the Ottoman Empire
In their last war with Venice, 1714–16, the Turks had little trouble beating the Venetians, especially on land, but they were fighting Austria at the same time, and lost that fight badly. The “great powers of Europe” (a post-Napoleonic group whose membership included England, France, Austria, Russia, and later in the 19th century Germany and Italy) were aware of the Ottomans’ weakness. When Christian peoples rose in rebellion against the empire, popular sympathy throughout Europe compelled the powers, even those most deeply committed to monarchy, to support the rebels’ cause. Such support was often cautiously limited; none of the powers expected, or wanted, to see the Ottoman Empire collapse all at once. This had less to do with respect for dynastic privilege than with mutually jealous calculations regarding who would get to pick up the pieces. In this French cartoon of 1908, you can see Kaiser Franz-Josef and Tsar Nicholas II picking up pieces labeled “Bosnia,” “Herzegovina,” and “Bulgaria.” (Austria-Hungary had recently announced its annexation of the first two Balkan provinces, which it was supposed to be superintending in the role of peacekeeper. Bulgaria declared its independence in the same year, but was accurately identified as a Russian protégé).

So, although the Turks might win military victories against rebels inside their empire, or against the infant kingdoms some of these rebels managed to set up during the 19th century, the great powers were certain to intervene in the peacemaking process and force the Ottomans to give back all or most of what they had gained. The common characterization of the empire at that time as the “sick man of Europe” was not altogether false, but at least some part of the illness was probably owing to the treatments of Europe’s doctors.