The Ottomans were known as one of the most formidable fighting forces in the early modern world—but how did they achieve that reputation, and how did it shape their empire? Ultimately, the Ottoman military was built on a system of merit, closely interweaving government, military service, and loyalty to the sultan. Part of this system was shaped by the empire's sheer diversity. For the Ottomans, religious identity was not necessarily paramount (though their tolerance did have limits). They sought to forge a different sort of identity—to be Ottoman was to be loyal.
This meritocratic ideal reached across the empire. The elite Janissary corps and the sipahis, cavalrymen who held timars (land grants) in return for service, formed the backbone of a system that rewarded ability and discipline over birth. Even succession followed a brutal version of this logic: under unigeniture, the sultan’s sons often fought one another for the throne, ensuring that only the strongest—and, ideally, the most capable—would rule.
Mehmed II may have earned the title “the Conqueror,” but under Suleiman the Magnificent, the empire reached its greatest extent. By the end of his reign, Ottoman territory covered nearly 880,000 square miles across Europe, Asia, and Africa. The empire also commanded a powerful navy that dominated the Mediterranean—until the defeat at Lepanto (1571) under Suleiman’s successor, Selim II. Like the Romans, the Ottomans relied on territorial expansion to secure resources, reward loyal soldiers, and sustain the empire’s military and administrative systems.
After the defeat of the Mamluks and the capture of the last Abbasid caliph, who had sought refuge in Egypt after the Mongol invasions, the Ottoman sultans claimed the title of caliph, spiritual leader of the Muslim world. As European powers expanded trade and influence in the Indian Ocean, the Ottomans defended Muslim interests, projecting naval power into the Red Sea, Persian Gulf, and Arabian Sea. Like Kublai Khan centuries earlier, early Ottoman rulers recognized that controlling the seas was vital to imperial power. In this way, the Ottomans also actively participated in the global age of maritime competition, expanding, protecting, and asserting their influence in both the Mediterranean and the Indian Ocean.
Ottoman Expansion
The Janissary Corps became the most efficient and disciplined standing army in Europe. Its soldiers were recruited through the devshirme system, which drew on young Christian boys from the Balkans and trained them for imperial service.
James Ludlow, “The Tribute of Children,” 1493
ABOUT a century before the capture of Constantinople, when Amurath I was on the throne, his vizier (advisor) suggested to him that he had a right not only to one-fifth of the spoils of battle, but also to one-fifth of the captives...To keep it up, the agents of the sultan went once in four years to all the Christian villages under Turkish [Ottoman] control...carefully selecting the strongest and most intelligent boys. The captives taken include Poles, Bohemians, Russians, Italians, and Germans. They are educated in the Mohammedan religion (Islam).
...Those [recruits] who have performed hard labor are made Janissaries (musketeers). Those who are educated in the seraglios [Palace Schools] become higher officers of state...The Janissaries are trained in shooting with the bow and arquebuse [musket]...Those who remain in the Palace Schools are trained in similar exercises, and also in study...They ascend [rise] to constantly greater pay, till they attain, perhaps, to one of the four great posts of the innermost chamber: beglerbeg [provincial governor], or a capitan deiri (admiral), or even of a vizier [adviser or minister]...Those who leave the palace enter into the four first corps of the paid sipahis [elite cavalry], who are in the immediate service of the sultan, and in whom he confides more than in his other bodyguards.
Janissaries and cannon batteries in 1543
Ottoman Janissaries Defending Budin, Under the Command of Suleiman The Magnificent, by Stanislaw Chlebowski.
As the empire expanded, the Ottomans faced multiple fronts: the Habsburg-led Holy League in Europe, the Safavids in Persia, and the Portuguese in the Indian Ocean. Competing with these powers required new military and fiscal systems.
Over time, the Timar system—which had granted land and tax rights to cavalrymen—was replaced by tax farming, in which revenue collection rights were auctioned to the highest bidder. This shift mirrored practices in parts of Europe and required a larger, more sophisticated bureaucracy.
By 1700, the Janissaries numbered more than 67,000, forming the backbone of a professional army. Yet as their influence grew, they also became deeply involved in imperial politics, much like the Praetorian Guard in Ancient Rome. They could act as kingmakers, backing or deposing sultans and often resisting reform—an early sign that a system founded on merit could also become a source of instability.
Ogier Ghiselin de Busbecq (1522 - 1592), diplomatic in service to the Habsburg Emperor Ferdinand I, description of the Ottoman military, The Turkish Letters
The Turkish state has 12,000 of these troops when the corps is at its full strength... These are the famous Janissaries, who inspire terror everywhere... On their side is the vast wealth and resources of their empire, experience and practice in arms, union, order, discipline, and watchfulness. On our side are found an empty treasury, luxurious habits, broken spirits, and quarrels between monarchs… Can we doubt what the result must be?”
“In making his appointments the Sultan pays no regard to wealth or rank... It is by merit that men rise in the service, a system which ensures that posts should only be assigned to the competent... Among the Turks, therefore, honors, high posts, and judgeships are the rewards of great ability and good service... This is not the case in Europe: with us there is no opening left for merit; birth is the standard for everything.
A German Engraving of Ibrahim Pasha, circa 1590
Born in Greece to a Christian family, Ibrahim was taken through the devshirme system and educated in the Ottoman palace schools, where he befriended the future Sultan Suleiman the Magnificent. His intelligence, loyalty, and administrative skill propelled him rapidly upward — first as a palace official, then as Grand Vizier after Suleiman’s accession.
As Grand Vizier, Ibrahim oversaw major military campaigns, including the conquest of Rhodes and Hungary, and helped manage diplomacy with Venice and the Habsburg Empire. His patronage of the arts and architecture also reflected Ottoman engagement with Renaissance ideas.
However, Ibrahim’s rise revealed the limits of meritocracy: his wealth and influence grew so great that he was perceived as a threat to the sultan. In 1536, Suleiman ordered his execution — a reminder that under Ottoman rule, power always flowed from the sultan’s favor.
Famous Corsair Hayreddin Barbarossa
A Sea Fight with Barbary Corsairs by Laureys a Castro, 1681
The Ottoman Empire’s military strength extended to the Mediterranean through corsairs—state-sponsored privateers who seized ships, raided coastal towns, and protected Ottoman trade. Raids targeted towns in Italy, France, Spain, Portugal, and even as far as the British Isles and Iceland, seizing merchant ships and captives to serve in the Ottoman navy. Some corsairs, like Hayreddin Barbarossa and Oruç Reis, were brought under Ottoman authority to command fleets, while others were renegades or converts from Europe seeking opportunity. Much like pirates in the Caribbean during the same period, Ottoman corsairs (aka Barbary Pirates) extended political and economic rivalries between states, acting as both instruments of imperial policy and independent actors pursuing profit and influence.
Corsairs participated in key naval engagements, including the Battle of Preveza (1538), which established Ottoman naval dominance, and Lepanto (1571), which marked the limits of Ottoman expansion. Through these actions, corsairs projected Ottoman power across the Mediterranean, protected Ottoman trade, disrupted European rivals, and reinforced the prestige of the empire.