The history of Spain in the sixteenth and seventeenth centuries was one of great upheavals, of expansions and conquests, as well as defeats and financial ruin. After the death of Fernando of Aragon in 1516, Charles I inherited the throne. In 1519 he was also crowned head of the Holy Roman Empire. The Spanish empire, under his rule, stretched to include the Spanish Kingdoms of Castile and Aragon, the European possessions of the Habsburgs, and vast colonies in the Americas. Charles I fought interminable wars against the Turks and the North Africans. After initial success at Tunis in 1535, his army was defeated twice, first in 1538 by Barbarossa, and then in 1541 at Algiers. Ultimately, Spain was unable to establish its supremacy over the Mediterranean.

In 1556 Charles I abdicated the throne in favor of his son Philip II. Battles against the Turks in the Mediterranean continued, but success came only in 1571. This victory changed the course of the history of Spain. It established Spain as the champion of Christianity. The Spanish continued their battles against the heretics, even in the face of ruinous costs. By the end of the century, Spain had declared bankruptcy twice. The history of Spain in the latter half of the16^th century is marked by many defeats. Unrest grew in the Netherlands, and ultimately led to the Eighty Years’ War. In 1580 Spain was compelled to sign a truce with the Turkish government. The Spanish navy or Armada was trounced by the British in 1588.

Philip II was succeeded by his son Philip III in 1598 and his grandson Philip IV in 1621. Both of them were ineffective rulers, and the history of Spain during this time is marked by more military defeats and territorial losses. In 1618, Spain was drawn into the Thirty Year’s War. In 1640, Portugal asserted its independence, and Catalonia became a virtual French province. In 1654, Spain was forced to grant independence to the northern Netherlands. Philip IV's successor, Charles II, was equally inept, and Spain gradually lost its power and prominence. The War of Spanish Succession (1702-1714) ensued, and the Bourbon Louis XIV of France finally assumed control of the throne. Under his rule the different Spanish kingdoms were unified. The rule of the Bourbons continued under Ferdinand VI and Charles III.

Charles III was an enlightened despot and the history of Spain during his reign is marked by prosperity. Though Spain lost in the Seven Year’s War against Britain, it helped to win the American Revolutionary War and once again became an international power to reckon with. A weak Charles IV was unable to carry on with his father’s reforms. Once again chaos descended, and Napoleon I invaded Spain in 1808 triggering Spain’s War of Independence. The little progress that had been made was wiped away, and Spain began to lag behind the other European powers in all respects.