The Spanish Empire, sometimes referred to as the Hispanic Monarchy or the Catholic Monarchy,Schneider, Reinhold, 'El Rey de Dios', Belacqva (2002)Hugh Thomas, 'World Without End: The Global Empire of Philip II', Penguin; first edition (2015) was a colonial empire that existed between 1492 and 1976. In conjunction with the Portuguese Empire, it ushered in the European Age of Discovery. It achieved a global scale, controlling vast portions of the Americas, Africa, various islands in Asia and Oceania, as well as territory in other parts of Europe. It was one of the most powerful empires of the early modern period, becoming known as "the empire on which the sun never sets". At its greatest extent in the late 1700s and early 1800s, the Spanish Empire covered , making it one of the largest empires in history.

Beginning with the 1492 arrival of Christopher Columbus and continuing for over three centuries, the Spanish Empire would expand across the Caribbean Islands, half of South America, most of Central America and much of North America. In the beginning, Portugal was the only serious threat to Spanish hegemony in the New World. To end the threat of Portuguese expansion, Spain conquered Portugal and the Azores Islands from 1580 to 1582 during the War of the Portuguese Succession, resulting in the establishment of the Iberian Union, a forced union between the two crowns that lasted until 1640 when Portugal regained its independence from Spain. In 1700, Philip V became king of Spain after the death of Charles II, the last Habsburg monarch of Spain, who died without an heir.

The Magellan–Elcano circumnavigation—the first circumnavigation of the Earth—laid the foundation for Spain's Pacific empire and for Spanish control over the East Indies. The influx of gold and silver from the mines in Zacatecas and Guanajuato in Mexico and Potosí in Bolivia enriched the Spanish crown and financed military endeavors and territorial expansion. Spain was largely able to defend its territories in the Americas, with the Dutch, English, and French taking only small Caribbean islands and outposts, using them to engage in contraband trade with the Spanish populace in the Indies. Another crucial element of the empire's expansion was the financial support provided by Genoese bankers, who financed royal expeditions and military campaigns.

The Bourbon monarchy implemented reforms like the Nueva Planta decrees, which centralized power and abolished regional privileges. Economic policies promoted trade with the colonies, enhancing Spanish influence in the Americas. Socially, tensions emerged between the ruling elite and the rising bourgeoisie, as well as divisions between peninsular Spaniards and Creoles in the Americas. These factors ultimately set the stage for the independence movements that began in the early 19th century, leading to the gradual disintegration of Spanish colonial authority.Lynch, John. "Spanish American Independence" in The Cambridge Encyclopedia of Latin America and the Caribbean 2nd edition. New York: Cambridge University Press 1992, p. 218. By the mid-1820s, Spain had lost its territories in Mexico, Central America, and South America. By late 1898, it had also lost Cuba, Puerto Rico, the Philippine Islands, and Guam in the Mariana Islands following the Spanish–American War.

Catholic Monarchs and origins of the empire

With the marriage of the heirs apparent to their respective thrones Ferdinand of Aragon and Isabella of Castile created a personal union that most scholars view as the foundation of the Spanish monarchy. The union of the Crowns of Castile and Aragon joined the economic and military power of Iberia under one dynasty, the House of Trastámara. Their dynastic alliance was important for a number of reasons, ruling jointly over a number of kingdoms and other territories, mostly in the western Mediterranean region, under their respective legal and administrative status. They successfully pursued expansion in Iberia in the Christian conquest of the Muslim Emirate of Granada, completed in 1492, for which Valencia-born Pope Alexander VI gave them the title of the Catholic Monarchs. Ferdinand of Aragon was particularly concerned with expansion in France and Italy, as well as conquests in North Africa.

With the Ottoman Turks controlling the choke points of the overland trade from Asia and the Middle East, both Spain and Portugal sought alternative routes. The Kingdom of Portugal had an advantage over the Crown of Castile, having earlier retaken territory from the Muslims. Following Portugal's earlier completion of the reconquest and its establishment of settled boundaries, it began to seek overseas expansion, first to the port of Ceuta (1415) and then by colonizing the Atlantic islands of Madeira (1418) and the Azores (1427–1452); it also began voyages down the west coast of Africa in the fifteenth century.Dutra, Francis A. "Portuguese Empire" in Its rival Castile laid claim to the Canary Islands (1402) and retook territory from the Moors in 1462. The Christian rivals Castile and Portugal came to formal agreements over the division of new territories in the Treaty of Alcaçovas (1479), as well as securing the crown of Castile for Isabella whose accession was challenged militarily by Portugal.

Following the voyage of Christopher Columbus in 1492 and first major settlement in the New World in 1493, Portugal and Castile divided the world by the Treaty of Tordesillas (1494), which gave Portugal Africa and Asia, and the Western Hemisphere to Spain.Burkholder, Mark A. "Spanish Empire" in The voyage of Columbus, a Genoese mariner, obtained the support of Isabella of Castile, sailing west in 1492, seeking a route to the Indies. Columbus unexpectedly encountered the New World, populated by peoples he named "Indians". Subsequent voyages and full-scale settlements of Spaniards followed, with gold beginning to flow into Castile's coffers. Managing the expanding empire became an administrative issue. The reign of Ferdinand and Isabella began the professionalization of the apparatus of government in Spain, which led to a demand for men of letters (letrados) who were university graduates (licenciados), of Salamanca, Valladolid, Complutense and Alcalá. These lawyer-bureaucrats staffed the various councils of state, eventually including the Council of the Indies and Casa de Contratación, the two highest bodies in metropolitan Spain for the government of the empire in the New World, as well as royal government in the Indies.

Early expansion: Canary Islands

Portugal obtained several papal bulls that acknowledged Portuguese control over the discovered territories, but Castile also obtained from the Pope the safeguard of its rights to the Canary Islands with the bulls Romani Pontifex dated 6 November 1436 and Dominatur Dominus dated 30 April 1437. The conquest of the Canary Islands, inhabited by Guanche people, began in 1402 during the reign of Henry III of Castile, by Norman nobleman Jean de Béthencourt under a feudal agreement with the crown. The conquest was completed with the campaigns of the armies of the Crown of Castile between 1478 and 1496, when the islands of Gran Canaria (1478–1483), La Palma (1492–1493), and Tenerife (1494–1496) were subjugated. By 1504, more than 90 percent of the native Canarians had been killed or enslaved.

Rivalry with Portugal

The Portuguese tried in vain to keep secret their discovery of the Gold Coast (1471) in the Gulf of Guinea, but the news quickly caused a huge gold rush. Chronicler Pulgar wrote that the fame of the treasures of Guinea "spread around the ports of Andalusia in such way that everybody tried to go there".Hernando del Pulgar (1943), Crónica de los Reyes Católicos, vol. I (in Spanish), Madrid, pp. 278–279. Worthless trinkets, Moorish textiles, and above all, shells from the Canary and Cape Verde islands were exchanged for gold, slaves, ivory and Guinea pepper.

The War of the Castilian Succession (1475–79) provided the Catholic Monarchs with the opportunity not only to attack the main source of the Portuguese power, but also to take possession of this lucrative commerce. The Crown officially organized this trade with Guinea: every caravel had to secure a government license and to pay a tax on one-fifth of their profits (a receiver of the customs of Guinea was established in Seville in 1475—the ancestor of the future and famous Casa de Contratación).Jaime Cortesão (1990), Os Descobrimentos Portugueses , vol. III (in Portuguese), Imprensa Nacional-Casa da Moeda, p. 551,

Castilian fleets fought in the Atlantic Ocean, temporarily occupying the Cape Verde islands (1476), conquering the city of Ceuta in the Tingitan Peninsula in 1476 (but retaken by the Portuguese), and even attacked the Azores islands, being defeated at Praia. The turning point of the war came in 1478, however, when a Castilian fleet sent by King Ferdinand to conquer Gran Canaria lost men and ships to the Portuguese who expelled the attack,The Canary's campaign: Alfonso de Palencia, Decada IV , Book XXXI, Chapters VIII and IX ("preparation of 2 fleets" [to Guinea and to Canary, respectively] "so that with them King Ferdinand crush its enemies" [the Portuguese] ...). Palencia wrote that the conquest of Gran Canary was a secondary goal to facilitate the expeditions to Guinea (the real goal), a means to an end. Alfonso de Palencia, Decada IV, book XXXII, chapter III: in 1478 a Portuguese fleet intercepted the armada of 25 navies sent by Ferdinand to conquer Gran Canary—capturing 5 of its navies plus 200 Castilians—and forced it to fled hastily and definitively from the Canary waters. This victory allowed Prince John to use the Canary Islands as an "exchange coin" in the peace treaty of Alcáçovas. and a large Castilian armada—full of gold—was entirely captured in the decisive Battle of Guinea.Pulgar, Hernando del (1780), Crónica de los señores reyes católicos Don Fernando y Doña Isabel de Castilla y de Aragon (in Spanish), chapters LXXVI and LXXXVIII ("How the Portuguese fleet defeated the Castilian fleet which had come to the Mine of Gold"). From the Biblioteca Virtual Miguel de Cervantes.