Question

Why were Europeans so interested in exploration in the 1400s and 1500s?

They wanted to spread Christianity.

They believed it was their destiny to spread across the globe.

They needed land for their growing populations.

They sought knowledge, power, and riches.

Answer 1

Most of these choices make some sense, but the one that probably encompasses all of them with a higher priority is the last one - they sought knowledge, power, and riches.

It's true that Christianity was a factor with missionaries being sent as far as Karakorum, the capital of the Mongol Empire during the 14th century, and that some European powers believed it was their destiny to spread across the globe, but the driving reasons behind most of these efforts was to learn more about the world. Later, power and riches were also key to these expeditions for an even wider variety of reasons, especially when merchants such as Marco Polo brought back accounts of their travels inflaming the imagination.

European nations were often engaged in one war or another at this time against each other, or in trying to stem the tide of the Ottoman Empire in the 15th century, and wars were expensive. But probably one of the biggest drivers were spices brought from the "Indies", a term collectively used to describe the Far East. Spices from China and India were valuable luxury items highly prized in Europe. Italian republics like Venice grew incredibly wealthy due to their maritime stranglehold over the trading routes.

In the 15th century, however, the Byzantine Empire had finally collapsed and a new power took control of the Middle East and Central Asia (in much of present day Turkey) called the Ottoman Empire. The empire sat right on the trading routes from the Far East and marked up the costs of spices to Europe, so what could they do? Explore and try and find a way around the Ottomans to the spices and other riches they wanted access to. It was also one of the reasons why Columbus was financed on his trip of discovery by Spain.