In terms of geopolitics, perhaps the most seminal event of the Middle Ages was the successful Ottoman siege of Constantinople in 1453. The city had been an imperial capital as far back as the fourth century, when Constantine the Great shifted the power center of the Roman Empire there, effectively establishing two almost equally powerful halves of antiquity’s greatest empire. Constantinople would continue to serve as the capital of the Byzantine Empire even after the Western half of the Roman Empire collapsed in the late fifth century. Naturally, the Ottoman Empire would also use Constantinople as the capital of its empire after their conquest effectively ended the Byzantine Empire, and thanks to its strategic location, it has been a trading center for years and remains one today under the Turkish name of Istanbul. 

In the wake of taking Constantinople, the Ottoman Empire would spend the next few centuries expanding its size, power, and influence, bumping up against Eastern Europe and becoming one of the world’s most important geopolitical players. It was a rise that would not truly start to wane until the 19th century, and in the centuries before the decline of the “sick man of Europe", the Ottomans frequently tried to push further into Europe. 

Some of those forays were memorably countered by Western Europeans and the Holy League, but the Ottomans’ most frequent foe was the Russian Empire, which opposed them for both geopolitical and religious reasons. From negotiations to battles, the two sides jockeyed for position over the course of hundreds of years, and the start of the fighting may have represented the Ottomans’ best chance to conquer Moscow and change the course of history. 

For anyone trying to understand the origins of modern Russia and the start of the Russo-Turkish Wars, the search should begin with Tsar Peter I (1672-1725), who titled himself Peter the Great during his lifetime. The moniker is fitting, considering the manner in which Peter brought Russia out of the Middle Ages and into the 18th century. Through a series of campaigns, Peter turned Russia into a formidable empire that would subsequently become a major force on the European continent, while also emulating Western Europe and turning Russia into an international state that interacted with the other continental powers. By revolutionizing and modernizing Russian arms, including the creation of Russia’s first naval force, Peter was able to pursue an aggressive and expansionist foreign policy that set the stage for the way the European map would be redrawn again and again over the coming centuries. 

In the late 17th century, Peter the Great launched an attack on Azov, an Ottoman fortress near the mouth of the Dnieper as it flows into the Sea of Azov. Conquest of the stronghold would provide Muscovy with a port and the ability to attack Crimea from sea, but even after the Russians accomplished this, the ultimate prize - free access to the Black Sea - remained out of Russia’s reach on account of the strength of the Ottoman fleet in the Black Sea and the logistical challenges of conquering the Crimean Peninsula. Furthermore, soon after the conquest of Azov Peter engaged in a much costlier war in the north against Sweden for the conquest of ports on the Baltic Sea. The Ottoman Empire, which had just signed a humiliating treaty with Austria, Poland and Venice which gave up Hungary and other conquests, was pleased with the respite, but it came unto conflict with Russia again over Peter’s enemy King Charles XII of Sweden, who had taken refuge in Ottoman Moldavia after his defeat at the Battle of Poltava in July 1709.