Ottoman imperialism climaxed under the reign of Suleiman the Magnificent (1520-1566). Before becoming the principle monarch for the Ottoman empire, Suleiman was active in other military activity, giving him a better eye for the battlefield. He was trained, intelligent, and fearless. These qualities allowed to him to successfully conquest many territories.
He conquered Baghdad in 1534, and Belgrade in 1521. After expanding the empire and proving himself, he made major changes in the education system, criminal law, and taxation.
Under his reign, the Ottomans became the leading naval power. The Ottomans inherited the navy of Mamluk rulers of Egypt. The strong Ottoman navy gave the empire an advantage over the others. They had naval trade dominance, creating new industries and essentially helping the economy prosper.
Suleiman was able to challenge Christian vessels in the Mediterranean and Portuguese fleets in the Red Sea and Indian Ocean. Suleiman stood a change against other great armies, and this allowed the Ottoman empire to expand and succeed all the way to the Persian Gulf.