In 1469, the crowns of the Christian kingdoms of Castile and Aragon were united by the marriage of their monarchs, Isabella I and Ferdinand II, respectively. 1478 commenced the completion of the conquest of the Canary Islands. In 1492, Jews were forced to choose between conversion to Catholicism or facing expulsion. As a result, as many as 200,000 Jews were expelled from Castile and Aragon.This was followed by expulsions in 1493 in Aragonese Sicily and Portugal in 1497. The Treaty of Granada guaranteed religious tolerance towards Muslims, for a few years before Islam was outlawed in 1502 in Castile and 1527 in Aragon, leading the remaining Muslim population to become nominally Christian Moriscos. About four decades after the War of the Alpujarras (1568–1571), a significant proportion of the moriscos were expelled, settling primarily in North Africa. From 1609 to 1614, over 300,000 Moriscos were sent on ships to North Africa and other locations, and, of this figure, around 50,000 died resisting the expulsion, and 60,000 died on the journey.
The year 1492 also marked the arrival of Christopher Columbus in the New World, during a voyage funded by Isabella. Columbus’s first voyage crossed the Atlantic and reached the Caribbean Islands, beginning the European exploration and conquest of the Americas, although Columbus remained convinced that he had reached the Orient. Large numbers of indigenous Americans died in battle against the Spaniards during the conquest, while more died from various new Eurasian diseases that travelled more quickly than the Spanish conquerors. The death toll during the initial period of Spanish conquest, from Columbus’s initial landing until the mid 16th century, is estimated as high as 70 million indigenous people out of a population of 80 million, as imported diseases such as smallpox, measles, influenza, and typhus decimated the pre-Columbian population. Disease killed between 50% and 95% of the indigenous population. Some scholars have described the Spanish conquest during this period as the largest genocide in history.
The Spanish colonisation of the Americas started with the colonisation of the Caribbean. It was followed by the conquest of powerful pre-Columbian polities in Central Mexico and the Pacific Coast of South America. Miscegenation was the rule between the native and the Spanish cultures and people. An expedition sponsored by the Spanish crown completed the first voyage around the world in human history, the Magellan-Elcano circumnavigation. The tornaviaje or return route from the Philippines to Mexico made possible the Manila galleon trading route. The Spanish encountered Islam in Southeast Asia and in order to incorporate the Philippines, Spanish expeditions organised from newly Christianised Mexico had invaded the Philippine territories of the Sultanate of Brunei. The Spanish considered the war with the Muslims of Brunei and the Philippines, a repeat of the Reconquista.
A centralisation of royal power ensued in the Early Modern Period at the expense of local nobility, and the word España, whose root is the ancient name Hispania, began to be commonly used to designate the whole of the two kingdoms. With their wide-ranging political, legal, religious and military reforms, the Hispanic Monarchy emerged as a world power.
The unification of the crowns of Aragon and Castile by the marriage of their sovereigns laid the basis for modern Spain and the Spanish Empire, although each kingdom of Spain remained a separate country socially, politically, legally, and in currency and language.
Two big revolts broke out during the early reign of the Habsburg emperor, Charles V: the Revolt of the Comuneros in the Crown of Castile and Revolt of the Brotherhoods in the Crown of Aragon.
Habsburg Spain was one of the leading world powers throughout the 16th century and most of the 17th century, a position reinforced by trade and wealth from colonial possessions and became the world’s leading maritime power. It reached its apogee during the reigns of the first two Spanish Habsburgs—Charles V/I (1516–1556) and Philip II (1556–1598). This period saw the Italian Wars, the Schmalkaldic War, the Dutch Revolt, the War of the Portuguese Succession, clashes with the Ottomans, intervention in the French Wars of Religion and the Anglo-Spanish War.
Through exploration and conquest or royal marriage alliances and inheritance, the Spanish Empire expanded across vast areas in the Americas, the Indo-Pacific, Africa as well as the European continent (including holdings in the Italian Peninsula, the Low Countries and the Franche-Comté). The first circumnavigation of the world was carried out in 1519–1521. The so-called Age of Discovery featured explorations by sea and by land, the opening-up of new trade routes across oceans, conquests and the beginnings of European colonialism. Precious metals, spices, luxuries, and previously unknown plants brought to the metropole played a leading part in transforming the European understanding of the globe. The cultural efflorescence witnessed during this period is now referred to as the Spanish Golden Age. The expansion of the empire caused immense upheaval in the Americas as the collapse of societies and empires and new diseases from Europe devastated American indigenous populations. The rise of humanism, the Counter-Reformation and new geographical discoveries and conquests raised issues that were addressed by the intellectual movement now known as the School of Salamanca, which developed the first modern theories of what are now known as international law and human rights. Juan Luis Vives was another prominent humanist during this period.
Spain’s 16th-century maritime supremacy was demonstrated by the victory over the Ottomans at Lepanto in 1571, and then after the setback of the Spanish Armada in 1588, in a series of victories against England in the Anglo-Spanish War of 1585–1604. However, during the middle decades of the 17th century Spain’s maritime power went into a long decline with mounting defeats against the United Provinces and then England; that by the 1660s it was struggling grimly to defend its overseas possessions from pirates and privateers.
The Protestant Reformation dragged the kingdom ever more deeply into the mire of religiously charged wars. The result was a country forced into ever-expanding military efforts across Europe and in the Mediterranean. By the middle decades of a war- and plague-ridden 17th-century Europe, the Spanish Habsburgs had enmeshed the country in continent-wide religious-political conflicts. These conflicts drained it of resources and undermined the economy generally. Spain managed to hold on to most of the scattered Habsburg empire, and help the imperial forces of the Holy Roman Empire reverse a large part of the advances made by Protestant forces, but it was finally forced to recognise the separation of Portugal and the United Provinces, and eventually suffered some serious military reverses to France in the latter stages of the immensely destructive, Europe-wide Thirty Years’ War. In the latter half of the 17th century, Spain went into a gradual decline, during which it surrendered several small territories to France and England; however, it maintained and enlarged its vast overseas empire, which remained intact until the beginning of the 19th century.
The decline culminated in a controversy over succession to the throne which consumed the first years of the 18th century. The War of the Spanish Succession was a wide-ranging international conflict combined with a civil war, and was to cost the kingdom its European possessions and its position as one of the leading powers on the Continent. During this war, a new dynasty originating in France, the Bourbons, was installed. The Crowns of Castile and Aragon had been long united only by the Monarchy and the common institution of the Inquisition’s Holy Office. A number of reform policies (the so-called Bourbon Reforms) were pursued by the Monarchy with the overarching goal of centralized authority and administrative uniformity. They included the abolishment of many of the old regional privileges and laws, as well as the customs barrier between the Crowns of Aragon and Castile in 1717, followed by the introduction of new property taxes in the Aragonese kingdoms.
The 18th century saw a gradual recovery and an increase in prosperity through much of the empire. The predominant economic policy was an interventionist one, and the State also pursued policies aiming towards infrastructure development as well as the abolition of internal customs and the reduction of export tariffs. Projects of agricultural colonisation with new settlements took place in the south of Mainland Spain. Enlightenment ideas began to gain ground among some of the kingdom’s elite and monarchy.