The Age of Exploration was a time of colonization and trade; the Crusades, having taken place in the Middle East, brought on a new age of trade, encouraged by spices and other valuables from the East. Spurred on by the invention of navigation devices like the astrolabe and innovations in shipbuilding, explorers like Christopher Columbus and Vasco da Gama carved out routes on the ocean for trade. The prosperity of trade, however, had dire consequences on the indigenous peoples of the new world. Countries during this time period pursued the policy of mercantilism, where a nation’s power is measured in the amount of gold it possesses.