In 1644 another expedition was fitted out against the island of Crete, which then belonged to the Republic of Venice. It had been bought many years previously from the Marquis of Montserrat, to whom it had been allotted as his share in the spoil of the Greek Empire, after the capture of Constantinople by the Crusaders in 1204.
It appears that a fleet of merchant vessels, on their way from Constantinople to Egypt, was captured by corsairs from Malta, who sought shelter for a time for themselves and their prizes in one of the ports of Crete. The Sultan was greatly incensed at this, the more so as some of the captured vessels belonged to one of the eunuchs of his harem. His first design was to send a fleet to attack Malta, but he was dissuaded from this course. He decided, as an alternative, to attack Crete, although the Porte was at peace with Venice, and the Republic was willing to make amends for the violation of its neutrality by the Maltese corsairs.
A fleet was thereupon fitted out, in 1645, ostensibly to attack Malta, but with sealed orders to divert its course when at sea to Crete. It consisted of a hundred and four vessels carrying upwards of fifty thousand men. The fleet, under the above orders, steered for Crete, and made a sudden attack on Canea, one of the chief ports of the island. Having captured this city and also Retino, the army was landed. It overran the whole island and invested Candia, its chief fortress and capital. A memorable siege then commenced. It lasted for nearly twenty-five years. The Republic of Venice made desperate efforts to save the city. It was not supported by the native Greek population of the island, who hated their Venetian rulers, and were not unwilling to exchange them for Ottomans.
While the Porte was thus engaged in the endeavour to add to its domain at the expense of the Republic of Venice, it was incurring a very serious shrinkage of Empire in the Mediterranean, along the northern coast of Africa. Historians agree in assigning to the middle of the seventeenth century the virtual severance from Ottoman rule of the two Barbary States of Algiers and Tunis. It is not possible to fix a precise date in either case, for the process of amputation was slow and was spread over some years, and long after the Sultan had practically ceased to exercise any real power over these dependencies the semblance and form of suzerainty was maintained. The main cause for the loss of these provinces was the practice which had grown up, under the corrupt administration of the Porte, of selling the posts of governors of them to the highest bidders in money. In place of men of energy and of capacity, able to control the unruly elements of mutinous soldiers and disaffected Moors and Arabs, governors were appointed under a system of purchase who were quite incapable of performing the duties of their office, and who merely thought of filling their pockets and recouping themselves for their outlay. The practice then arose for the Janissaries and other Ottoman soldiers forming the garrisons of Algiers and Tunis to elect their own chiefs. The appointments of these men, Deys, as they were called, were for a time submitted to the Sultan for approval or veto, but later this form was discontinued, and the Deys elected by the soldiery became the real dominant authorities in these States, and eventually superseded in form, as well as in substance, the feeble pashas sent nominally as governors from Constantinople. Virtual independence was thus achieved. Both States provided themselves with fleets of powerful war vessels, which roamed over the Mediterranean and the Atlantic as far as the coasts of Ireland and Madeira, preying upon the commerce of all countries, irrespective of whether they were at war with the Porte or not. They were, in fact, pirates. The captured crews were employed as slaves in the bagnios of Algiers and Tunis. The best evidence of the actual, though not yet of the formal, independence of these Barbary States was that other Powers sent their fleets to attack and bombard them, and to destroy, if possible, their pirate craft, without declaring war against the suzerain power, the Porte. Thus, as early as 1617 a French fleet, under Admiral Beaulieu, made an attack on the Algerian fleet of forty vessels of from two hundred to four hundred tons, and destroyed many of them. In 1620 a British fleet, under Sir Richard Mansel, in retaliation for the capture of no less than four hundred British merchant ships in the previous five years, made a similar attack on Algiers, without, however, much result. In 1655, another British fleet, commanded by Admiral Blake, under orders from Protector Cromwell, bombarded Tunis, and destroyed a great part of its fleet, and having effected this proceeded to Algiers. There was much consternation there, and the captives of British birth were given up without a struggle. In both these cases there was no declaration of war against the Porte, and no offence was taken by the Sultan at the action of England.
In 1663 the British Government made a treaty with the Sultan empowering it to attack and punish the Algerines without being charged with a breach of amity with the Porte. It frequently availed itself of this, and many naval attacks were made on these nests of pirates, without, however, very effectual results. In some of its naval operations in the Ægean Sea the Porte received assistance from the fleets of these two Barbary States. But this was entirely at the discretion of their virtual rulers and was not considered obligatory on them. For our present purpose, it is sufficient to point out that the States became virtually independent of the Ottoman Empire about the year 1650. In the case of Algiers this independence continued till the State was conquered and annexed by France in 1830. In Tunis the same process took place, with the difference that an hereditary Beyship was eventually formed under a Greek adventurer whose descendants retained power there till 1881, when the French invaded the province and eventually annexed it to France.
Ibrahim was succeeded by his son, Mahomet IV. He reigned for thirty-nine years. During the first eight of these there was chaos in the Empire. The government remained in the hands of the harem. The position was aggravated by fierce dissension in that institution. There were two rival parties, the one led by the ex-Sultana Validé, the mother of the late Sultan, who was loath to part with the power she had acquired during her son’s reign, the other by the mother of the new Sultan, Torchan by name. Both of them had their supporters among the Janissaries and Spahis, with the result that there were frequent disorders and encounters in the streets of the capital. Grand Viziers were made and deposed with startling rapidity, as one or other of these parties prevailed. Outbreaks occurred in many parts of the Empire and there was no one with sufficient authority to cope with them. The dispute between the two ladies was eventually settled by the murder of the elder one. Meanwhile it was fortunate for the Empire that Austria was so exhausted by thirty years of war in Germany that she was not able to avail herself of the opportunity afforded to invade the Ottoman Empire and recover Hungary and other provinces. But the war with Venice resulting from the unprovoked attack by Ibrahim on Crete was continued without intermission. A Venetian fleet under command of Admiral Macenigo defeated and destroyed an Ottoman fleet off the Dardanelles and took possession of the islands of Lemnos and Tenedos. It blockaded the Dardanelles. Strange to say, this did not put a stop to the siege of Candia by the Ottomans. This was maintained with pertinacity, but for a long time without success. Meanwhile anarchy prevailed in the Empire. Relief most unexpectedly came from the appointment of a Grand Vizier by Sultana Torchan, by which she made some amends for her previous misdeeds.