How did European exploration lead to imperialism?

As new areas of the world were discovered or came to the attention of European explorers for the first time, new opportunities for trade and exploitation of resources fueled a competition among the merchant classes of Europe. Competition not only for resources but also for sponsorship of discovery voyages led to the various states of Europe seeking to claim the most overseas territory, initially for financial gain and later for colonization. Fierce competition created rival states and affected politics within Europe, with the primary players being Spain, France, England, and the Dutch states. Portugal, too, ventured into this arena, though largely in providing ships for hire and obtaining control over Africa, and thus the slave trade, following the Treaty of Tordasillas in 1494.