The wealth of the East trickled into Western Europe mainly by overland routes. Goods changed hands many times before they reached the consumer, and at each exchange the cost increased.

Shipping costs were also high. Goods were transported by camel or horse caravans, each animal carrying only a comparatively small load. After 1453 the Moslem Turks controlled Constantinople, which was the crossroads of important trade routes. They permitted cargoes from the East to pass through the city only on their own terms.
Western European merchants thought that if they could find sea routes to the Orient they could import goods directly to their own cities. Soon they were prepared to outfit ships for sea captains sailing in search of new routes. Each
contributed only a portion of the expense, so that no one would be completely ruined if the venture failed.

They also secured the king's approval of their
enterprises and his promise to defend their claims to lands discovered along the
way. The king of Spain always demanded a fifth of the gold and silver found by his explorers.
The Italian port cities were satisfied with their monopoly of the old routes. The Scandinavian countries were far removed. Germany was split into many small
states. Thus the work of discovery fell to Portugal, Spain, England, and France.