New Spain (Spanish: Nueva España) was the colony comprising Spain's possessions in the New World north of the Isthmus of Panama. It was established following the Spanish conquest of the Aztec Empire in 1521, and following additional conquests, it was made a viceroyalty (Spanish: virreinato) in 1535. The first of four viceroyalties Spain created in the Americas, it comprised Mexico, Central America, much of the Southwestern and Central United States, the Spanish West Indies, Spanish Florida, and eventually, the Philippines and other Pacific islands.After 1535. the colony was governed by the Viceroy of New Spain, an appointed minister of the King of Spain, who ruled as monarch over the colony. The capital was Mexico City.New Spain lost parts of its territory to other European powers and independence, but the core area remained under Spanish control until 1821, when it achieved independence as Mexico. It developed highly regional divisions, which reflect the impact of climate, topography, the presence or absence of dense indigenous populations, and the presence or absence of mineral resources. The areas of central and southern Mexico had dense indigenous populations with complex social, political and economic organization. The northern area of Mexico, a region of nomadic and semi-nomadic indigenous populations, was not generally conducive to dense settlements, but the discovery of silver in Zacatecas in the 1540s drew settlement there to exploit the mines. Silver mining became the motor of not only the economy of New Spain, but vastly enriched Spain, and transformed the global economy. New Spain was the New World terminus of the Philippine trade, making the viceroyalty a vital link between Spain's New World empire and its Asian empire.