Many Albanian converts to Islam migrate elsewhere within the Ottoman Empire in the early seventeenth century and find careers in the Ottoman military and government.

Some attain powerful positions in the Ottoman administration.

About thirty Albanians rise to the position of grand vizier, chief deputy to the sultan himself.

In the second half of the seventeenth century, the Albanian Kopriilu family provides four grand viziers, who fight against corruption, temporarily shore up eroding central government control over rapacious local beys, and win several military victories.

Köprülü Fazil Ahmed Pasa, the eldest son of Köprülü Mehmed Pasa, who had chosen for him a career in the learned professions, had at 16 been made a professor, but entered the Ottoman civil service when his father became grand vizier.

He had been made governor-general of Erzurum (1659) and then Damascus (1660) before he is called as deputy grand vizier during an illness of his father.

Fazil Ahmed Pasa on November 1, 1661, succeeds his father as grand vizier under the Ottoman sultan Mehmed IV.

The Turkish force in Transylvania, having restored order, is regarded by the populace as an army of liberation from Habsburg tyranny.

Led by Fazil Ahmed Pasa and enlarged by Wallachian and Transylvanian Christians offended by the Habsburg Counter-reformation, it overruns the Hungarian-Transylvanian areas in 1663, capturing Buda and, in a surprise attack in September, overwhelming the fortress of Érsekùjvar (Nové Zámky, or Neuhäusel, in present Slovakia) in a victory second only to Mezo-Kersztes in the Austro-Turkish war of 1591-1606.

The Turks had failed to conquer it six times before.

It is made the center of a Turkish eyalet in present-day southern Slovakia—with the subordinate sanjaks of Litra, Leve, Novigrad, Holok, Bukabak and Şefradi (probably Šahy).

The Slovak saying "Strong as a Turk in front of Nové Zámky", which means working with determination and stability, reflects the memory of the determination of the Turks to conquer the fortress.

The interference by the Ottoman Empire in the affairs of Transylvania, always an unruly district, has brought on a war with the Holy Roman Empire, which after some desultory operations really begins in 1663.

Fazil Ahmed Pasa proves as energetic and skillful as his father in asserting his authority.

When, during Fazil Ahmed Pasa’s first campaign against the Austrians in 1663, he learns of a plot against himself fomented by Sâmî-zâde Mehmed, chief of the secretaries and member of the clique who had brought his father to power, he does not hesitate to have him executed.

Fazil Ahmed Pasa’s failure at the Battle of St. Gotthard had tarnished his earlier success against the Austrians, but his ability to make a treaty favorable to the Ottomans at Vasvar pleases the the sultan, who receives him in Edirne with great favors.

The French, apparently chastened by their failed relief effort and the loss of so valuable a warship, had abandoned Candia in August, leaving Captain General Francesco Morosini, the commander of Venetian forces, with only thirty-six hundred fit men and scant supplies to defend the fortress.

He, therefore, accepts terms and surrenders on September 27, 1669, to Grand Vizier Ahmed Köprülü.

However, his surrender without first receiving authorization to do so from the Venetian Senate is to make Morosini a controversial figure in Venice for some years afterward.

A peace treaty leaves most of Crete in Turkish hands.

As part of the surrender terms, all Christians are allowed to leave Candia with whatever they can carry while Venice retains possession of Gramvousa, Souda and Spinalonga, fortified islands that shield natural harbors where Venetian ships can stop during their voyages to the eastern Mediterranean.

Fazil Ahmed Pasa’ conquest of Candia, ending a siege of twenty-eight months—possibly the longest siege in history—and thus terminating a long and dangerous war with Venice, wins him unparalleled prestige.

Venice, a ruling force in the eastern Mediterranean for about five hundred years, now has little effective power here.

Following the loss of Candia, the the Venetians will somewhat offset their defeat by expanding their holdings in Dalmatia.

Ottoman imperial decadence is finally halted by a notable family of imperial bureaucrats, the Koprulu family, which for more than forty years (1656-1703) provides the empire with grand viziers, combining ambition and ruthlessness with genuine talent.

Mehmet, followed by his son Ahmet, overhaul the bureaucracy and institute military reforms.

Crete and Lemnos are taken from Venice, and large provinces in Ukraine are wrested temporarily from Poland and Russia.

The Koprulu family also resumes the offensive against Austria, pushing the Ottoman frontier to within one hundred and twenty kilometers of Vienna.

An attempt in 1664 to capture the Habsburg capital is beaten back, but Ahmet Koprulu extorts a huge tribute as the price of a nineteen-year truce.

When it expires in 1683, the Ottoman army again invades Austria, laying siege to Vienna for two months, only to be routed ultimately by a relief force led by the king of Poland, Jan Sobieski.

King Michael Wisniowiecki, a native Pole and descendant of Korybut, brother of King Wladyslaw II Jagiello, had in 1669 been freely elected by the unanimous vote of the Polish nobility but had been chosen chiefly for the merit of his father, Jérémi Wisniowiecki, a great border magnate.

The senior Wisniowiecki had kept in check the Cossacks who, allied with Turks and Tatars, had refused to accept Polish authority in the western Ukraine after the Russo-Polish War of 1658-57; they continue to stage bloody raids in the region.

The junior Wisniowiecki proves to be a passive tool in the hands of the Habsburgs.

The French party, in view of this, rallies round Jan Sobieski, a military commander of rising fame.

Unprepared for war, and torn by internal conflict between the king and the szlachta nobility, the Commonwealth Sejm cannot act to raise taxes and gather a larger army The dissensions between the two camps cost Poland a new defeat at the hands of the united Turks and Cossacks.

Ottoman grand vizier Köprülü Fazıl Ahmed always has the support of the sultan against those who belittle and struggle against him.

Whenever he is away from the capital, Kara Mustafa, husband of his sister, is left as his deputy.

In the battlefield, he also has the close cooperation of Gürcü Mehmed, Kaplan Mustafa, his brother-in-law, and other able generals.

The prestige of the empire that his father had reestablished is so great as to bring under his command during his campaigns in central Europe the auxiliary forces of the vassal principalities—Transylvania, Moldavia, Wallachia, and the Crimean Khanate.

He has also followed his father's reforms aiming at reducing the number of the Janissaries (the core of the Ottoman standing army) and spahis (the Ottoman cavalry) and makes them more efficient by restoring discipline among them.

Köprülü Fazıl Ahmed also places emphasis on the age-old Ottoman policy of protection of the reaya (non-Muslim taxpayers), which is possible only under a strong central government.