A generation before Lepanto, the Ottoman Empire was a superpower due to its vast human and economic resources and military and naval power. In the first decade of Sultan Süleyman’s reign, the empire’s revenues are estimated at almost 11.5 million gold ducats. However, in the last years of his reign, revenues of the central treasury decreased to 3 million gold ducats, as opposed to 4.8 ducats in 1527-28, and the treasury had 110,000 and 370,000 ducats deficits in 1565-66 and 1566-67. Still, revenues increased to 3.8 million ducats next year, and the treasury closed the fiscal year with a positive balance. It was not until 1592 that the treasury faced recurring deficits. 

The vast empire of the Habsburgs possessed human and economic resources comparable to those of the Ottomans. However, unlike the padishah’s territorially contiguous “wellprotected domains,” the Spanish Habsburgs had a discontinuous empire with territories loosely arranged and scattered all over Europe and overseas. Charles V’s combined revenue from Castile, the Kingdom of Naples, and the Low Countries’ core provinces amounted to about 4.8 million Spanish ducats in 1540. However, Castile alone collected 10 million ducats by the end of the century. Ferdinand I, Charles’ brother and the Ottomans’ main rival in central Europe collected about 1.9 million Venetian ducats annually. The revenues of the Republic of Venice, the Ottomans’ maritime rival in the eastern Mediterranean, were equally modest: about 2 million ducats before 1570.

The padishah had a professional army of 125,00-130,00 men at his disposal, which reached 160,000-170,000 men with the auxiliary raiders (akıncı) and the infantry peasant militia (azab). The professional army consisted of 70,000-80,000 provincial cavalrymen remunerated by military fiefs (timar). The number of the salaried standing troops of the Porte (kapukulu) fluctuated between 15,000 and 19,000 soldiers before Lepanto. Süleyman routinely mobilized 60,000 to 70,000 troops for his campaigns.

Initially, neither Charles V nor Ferdinand had a standing field army. Both had to raise armies anew for each new campaign and negotiate with the Estates of their respective kingdoms to get the troops and funds necessary to pay them. However, when not fighting against his Valois rival in Italy, Charles V could assemble an army comparable in size to that of Süleyman’s. In 1532, contemporary estimates put the combined military force of the Habsburg brothers at 160,000 to 220,000 men. No wonder, Neither Charles nor Süleyman risked an open battle. The Venetians had a modest standing force, 6,750 men in about 1550 and 9,279 men by 1582, but in wartime, such as the war years of 1570-73, the Republic was capable of maintaining an average of 33,400 soldiers.  

The Ottomans’ naval superiority rested not on the quality of their ships but the empire’s ample natural and human resources and efficient organization. In Istanbul, the main Ottoman Arsenal (Tersane-i Amire) had 160 docks by 1515. Between 1527 and 1531, it built 61 ships and repaired 146 vessels. The Venetian bailo in Istanbul reported in 1558 that the Ottomans could build and outfit 130 ships without difficulty, although he considered them of inferior quality, made with green timber. Four years later, the secretary of the bailo claimed that the Ottomans could deploy 170 galleys “for long voyages” and some 200 “for short ones,” plus those that the corsairs owned.

Charles V’s Mediterranean fleet was under the able leadership of Andrea Doria, the Genoese maritime condottiere. The fleet consisted of Doria’s galleys, galley squadrons from Spain, Sicily, Naples, and other hired galleys from Italy. For major naval campaigns, the emperor could mobilize several hundreds of vessels and tens of thousands of troops. For his Tunis campaign in 1535, he mobilized over 400 vessels and 50,000 men. The Venetians also had a strong navy. In the mid-sixteenth century, in the Venetian Arsenal, 120-130 light galleys (galie sotili), 6-12 large galleys (galie grosse), and 12-21 flagships (galee bastarde) were built or under construction. The Arsenal had 100 light galleys, four to ten great galleys, eight biremes, and 16 light dispatch and scouting vessels. Of these vessels, 25 galleys were held in basins, armed and equipped, ready to be dispatched at short notice. The rest of the fleet was kept on land, complete in hull and superstructure, and could be launched after caulked.

As can be seen, only the joint military and naval might of Spain, Venice, and their allies could successfully challenge the Ottomans. This was the case at the Battle of Lepanto in 1571. Still, the numbers of vessels recorded in various contemporary sources (202 to 219 galleys and six galleasses on the Christian side instead of 205 galleys and 35 to 68 galiots on the Ottoman side) are misleading. They exclude the smaller transport ships in both navies and the galiots and frigates in the Christian fleet. The Holy League slightly outnumbered the Ottomans in terms of combatants and auxiliaries: 62,100 men to 57,700 men. More importantly, the league had a substantial advantage in firepower: 1,334 to 741 guns. Ottoman accounts also underlined that their fleet suffered from a shortage of manpower. Many died during the 1571 campaign, and the soldiers aboard the coastal begs’ ships had already returned home for the winter.

Following the destruction of the Ottoman fleet at the battle, the abundance of Ottoman resources and efficient resource management enabled the Ottomans to rebuild their navy. The strength of the rebuilt Ottoman navy was estimated at between 180 and 230 ships in 1572. The resurgence of the Ottoman navy forced the Venetians to conclude a separate treaty with the padishah in 1573. Although in 1573 the Spanish conquered Tunis, in 1574 a large Ottoman fleet of some 240 galleys, 16 galleasses, three galleons, and other ships under Kılıç Ali Pasha’s command conquered La Goletta (Halk al-Wadi), which the Spanish had held since 1535, and retook Tunis. The victory—off the coast of Spanish Habsburg, Sicily at such a great distance from Istanbul, the logistical center of Ottoman operations—demonstrated Ottoman naval resurgence and restored Ottoman military prestige. However, these wars exhausted the belligerents who concluded a treaty in 1580 to attend to more pressing concerns in the Netherlands and Persia. Spain, Venice, and the Ottomans all faced significant financial difficulties, negatively affecting their naval power.