In the 17th century Turkey was a major world power and the first decades of the reign of Mehmed IV (1648-1687) was a period of great success. In the 1660s Turkey was involved in the war with Venice and Austria and in 1669 Crete was finally conquered after years of bloody struggle. The Ottoman army was perceived as numerous, well equipped and prepared for war, especially siege operations.
Apart from the war with Poland (1672-1676) which concluded with the capture of Podole, Turkey waged a bloody war against Moscow (1674-1681). In the 1670s there were minor signs of the weakening of the Ottoman Empire, however it still possessed huge mobilization capabilities. It is estimated that the army under Kara Mustafa which seized Chyhyryn in 1678 numbered up to 115,000 men.
From the Ottoman position, the Polish Lithuanian Commonwealth, Cossacks, and Moscow were peripheral to their main rivals – the neighboring Persians to the east and the Holy Roman Empire to the west. The Ottoman also strove to control the eastern Mediterranean and waged a twenty-four year war with Venice for the control of Crete in modern day Greece. The war for Crete (1645-1669) turned out to be extremely important and bloody, but the Ottomans achieved their objective. It is estimated that the war for Crete cost Turkey about half a million of casualties. A significant share of these losses came from galley soldiers and oarsmen, as the Venetian fleet was technically superior. However, the siege of Candia brought about much needed military reforms and the Ottomans to improve their abilities in waging siege warfare.
From 1661 to1664 Turkey was in conflict with the Holy Roman Empire. It is estimated that in 1663 the Ottomans mobilized an army of almost one hundred thousand soldiers. This force was also supported by additional Tatar troops. Despite the defeat of Saint Gotthard (Szentgotthard) in 1664, Turkey emerged victorious. The resulting Treaty of Vasvar gave the Ottomans a number of castles in Upper Hungary and Prince Michael I Apafy, a Turkish vassal, became the ruler of Transylvania.
To protect their northern borders, the Ottomans relied heavily on their vassals, the Crimean Tatars. Since the Tatars also benefited from Turkish protection, they often fought on their behalf. The Tatars commonly fought against the Polish Lithuanian Commonwealth and Moscow, but they also fought against Austria, which was then part of the Holy Roman Empire. In 1663 Tatars under the command of Sultan Ahmed Girai raided Hungary, where they pillaged, burned and terrorized the population. The Ottomans relied upon the Tatars to augment their armies, to serve as an advanced guard and to screen the main Turkish army.
The Ottoman Empire reached its height in the seventeenth century and straddled three continents. To many, it appeared its financial and human resources were endless. The large size of the Empire impacted its ability to adapt to changing conditions – the military machine was lumbering and mobilization for large campaigns took a very long time. Yet in spite of budgetary deficits, which reached their peak during the reign of Kara Mustafa, the Turks were able sustain extensive military operations, including being at war for thirty-five years (1645-1680).