By the 1500's, Italy controlled Europe's trade with India and other parts of Asia. To break the Italian hold on trade, other European nations began to search for an all-water route to the east. They hoped their journeys would enrich their countries and spread Christianity.

A number of developments - such as more accurate maps, improved ships, and better navigation instruments - aided European explorers. One instrument was the compass, which has a magnetic needle that always points north. Another was the astrolabe, which measures the angle of the stars and helps sailors find latitude. These journeys changed world history forever.