Five hundred and twenty-one years ago today, as the summer of 1492 turned to fall, Christopher Columbus and his expedition were somewhere on the North Atlantic, several weeks away from the discovery that would make him–and them–famous. Most of us know the story of Columbus’s voyage, his idea to sail west to find a route to India, his difficulty in gaining backing, and the ultimate semi-success of his efforts; I say semi because he failed to find India, although he believed until the end of his life that he had. What fewer people understand is why this epic voyage happened, and it has a lot more to do with the history of Byzantium than most realize.

The Byzantine Empire breathed its last on the morning of May 29, 1453, as Turkish Sultan Memhet II led his troops to sack the city that had so long eluded the Islamic world. In 1453 Christopher Columbus was just a baby in Genoa. But the fall of Constantinople had already shaped his fate. Although few Christians in Western Europe cared enough about the fate of Byzantium to send it any real help against the Ottoman Turks, European countries depended on Constantinople for much of their economic livelihood. It was the commercial link between Europe and the Silk Road that had stretched across Asia for centuries. A huge part of the medieval world economy was powered by spices, silk, and gold coins that traveled across this road, on a treacherous journey across the steppes and deserts of central Asia to China and points beyond.

After 1453, travel for Europeans on the Silk Road virtually ended. The various powers in central Asia that had previously facilitated travel and commerce on the Silk Road, such as the Mongols, had already begun to decline, and the Ottomans busied themselves with both consolidating their own empire in the Middle East and, especially in the 17th century, extending it into southeastern Europe. Indeed, in the decades after 1453, Europe fell into what we might today call a recession. Asian goods weren’t reaching markets in Europe, where in some places, such as Italy, demand was growing, not shrinking. Something had to be done.

silk road

Early modern trade routes: red is land, the “Silk Road,” and blue are water routes. Click for larger/more detail.

The Portuguese pioneered the idea of reaching the Orient over water as opposed to land. Indeed, you can argue that the fall of Constantinople jump-started the Age of Exploration. The Portuguese, making use of what Europeans knew about the world in the late 15th century, rationally decided to sail east around the horn of Africa to reach India, Southeast Asia and China. The Indian Ocean had been a hub of trade for much of the Middle Ages, so why not capitalize on what you had?

Columbus, by the 1480s a navigator and adventurer in his own right, turned this idea on its head. Why not sail west, not east? It is not true that most people in 1492 thought the world was flat. We have known since Greek times that the world was round, and even measured (correctly) its circumference. Columbus did think that reaching Asia by sailing west was far more feasible than most Europeans assumed, however. It was that assumption that sold Ferdinand and Isabella, and in August 1492 the anchors of Columbus’s ships raised for the last time before they touched the waters of the New World.

The Byzantines, with their passion for eschatology, had a prophecy that predicted the end of the world. One  Byzantine theologian, I forget who, had fixed the date for the end of all things–and calculated it as what would ultimately be the year 1492. The Byzantine world ended in 1453, but forty years later you could say that, in a sense, the world did end with Columbus’s discovery–at least the world as it was known at that time. So the Byzantines were, in their own way, right.