European conquest of the New World was motivated by European nation-states' need to gain increasingly scarce resources, compounded by rivalry between nations. By the 15th and 16th centuries, European resources were depleting. Each nation-state looked aggressively for new land, and explorers discovering new terrain took possession in the name of the sponsoring nation. Discovery of new land was followed by rapid and aggressive attempts at colonization.
The Need for Timber
Europe was rebounding from the plague, with populations and commerce rebuilding. Sailing ships acted as the primary vehicles that transported goods and commodities. After centuries of deforestation, the availability of large timbers required not only for ships, but also for new buildings was limited. Finding abundant resources of mature timber for building ships and housing was a critical need for all European nation-states. The New World offered an abundance of large timber, making it an appealing source of lumber.
The Search for Gold
The search for precious metals -- especially gold -- drove expeditions in the 15th and 16th century. Gold artifacts and precious metals funded the expensive process of colonization, with explorers searching aggressively for precious metals. Some of this search was fueled by exploits of early explorers. In 1519, Spanish explorer and military leader Hernan Cortez, legendary for his search for gold, led Spanish troops to the Aztec empire in Mexico. Upon arriving in Mexico's capital city, Cortez received substantial gifts of gold from the Aztec leader. The Aztecs intended the gold to placate the European visitors, but their gifts had the opposite effect. Ultimately, the Aztec capital, known today as Mexico City, was besieged by Cortez, who claimed it -- and its gold -- for Spain in August of 1521.
In addition to natural resources, conquered territories supplied human capital, most frequently in the form of slavery. Cortez's conquest of Mexico meant not only control of natural resources, but also enslavement of the peoples of Mexico, who were required to work as agricultural laborers, builders and miners. During the process of European colonization, this process of enslavement and control was repeated throughout the New World. Indigenous peoples were enslaved and set to work producing commodities for export to the Old World.
Rivalry between European monarchs also drove competition in finding lands to be claimed for the glory of the nation -- and for the glory of the monarch. Most royal families were distantly related through the centuries-old tradition of marriage to create alliances, and being the best or wealthiest in terms of resources and achievement drove many monarchs to pay explorers, such as Christopher Columbus and Amerigo Vespucci, to find new territory for expansion. More land and more resources equated to higher status and more prestige -- and personal glory.