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.

The end of the Byzantine Empire had a profound effect not only on the Middle East but Europe as well. Constantinople had played a crucial part in the Crusades, and the fall of the Byzantines meant that the Ottomans now shared a border with Europe. The Islamic empire was viewed as a threat by the predominantly Christian continent to their west, and it took little time for different European nations to start clashing with the powerful Turks. In fact, the Ottomans would clash with Russians, Austrians, Venetians, Polish, and more before collapsing as a result of World War I, when they were part of the Central Powers.

It was also roughly around this time that a period of European exploration began, and major factors that contributed to this period of exploration were introduced by the Chinese, albeit indirectly. The magnetic compass had already been developed and used by the Chinese sailors since the 12th century, although it had first been created in the 3rd century BCE as a divination device. The Song Dynasty then began using the device for land navigation in the 11th century and sailors began using it shortly after. The technology slowly spread west via Arab traders, although a case can be made for the independent European creation for the compass (Southey 1812: 210). Regardless, by the 13th century the compass had found its way to Western traders, coming at a time that trade had been increasing across Europe.

Trade was able to increase in Europe around the world due to more effective ships being introduced, and some of the improvements that were made to the ships were first introduced by the Chinese. The introduction of multiple mast ships and the sternpost rudders allowed the ships to travel quicker and be more maneuverable. By the start of the 15th century, ships were now much larger and able to support long distance travel with a minimum number of crew aboard.

With that, the Portuguese started exploring the west coast of Africa and the Atlantic under orders from Prince Henry the Navigator. At this point, Europeans had not yet been capable of navigating completely around Africa since the ships being built were not yet fully capable of being able to sail very far from the coast and navigation in open waters was difficult, but the Portuguese continued pushing down the western African coast looking for ways to bypass the Ottomans and Muslims of Africa who had been making overland trade routes difficult. In 1451, Prince Henry the Navigator helped fund and develop a new type of ship, the caravel, that featured triangular lateen sails and would be able to travel in the open ocean and sail against the wind.

At the same time, this also ensured that the Portuguese were entering an Ottoman sphere of influence. When the Portuguese broke into the Indian Ocean, trade was passing along routes that were centuries old. Thus, even while the Ottomans were encroaching on European lands to their west, the Europeans were encroaching on Ottoman domains further east, and the stage was set for a series of conflicts featuring the vast Ottoman Empire.