Ferdinand died on Jan. 23, 1516, and the crowns of the Spanish kingdoms devolved on his grandson, Charles I (1516-56), the ruler of the Netherlands and heir to the Habsburg dominions in Austria and southern Germany. When Charles arrived in Spain, in September 1517, the country was apprehensive of the rule of a foreigner. Charles, inexperienced, speaking no Spanish, and surrounded by Burgundian councillors and courtiers, did not initially make a good impression. The different Cortes of Castile, Aragon, and Catalonia granted his financial demands but attached to them much pointed advice and criticism.
On June 28, 1519, Charles was elected Holy Roman emperor as Charles V and prepared to go to Germany. As Charles set sail (May 20, 1520), the Castilian revolution had already begun. The towns, led by Toledo, formed a league and set up a revolutionary government. When the more radical and popular elements in the cities were gaining control of the comunero movement and beginning to spread it to the nobles' estates did the nobles combine to raise an army and defeat the comunero forces at Villalar (April 23, 1521).
After Villalar the Spanish nobility had come to accept Charles I. His championing of Roman Catholic Christianity against the Muslim Turks and German heretics appealed to their own traditions of Christian warfare against the Muslims in the Spanish Peninsula and North Africa. Even though Charles spent only 16 of the 40 years of his reign in Spain, the Spanish upper classes were beginning to accept and enjoy their monarch's position as the greatest ruler in Europe.
Spain as a result, however, became involved in interminable wars. The necessity of defending southern Italy from the Turks brought Charles's empire into collision with the Ottoman Empire, with the central Mediterranean as the chief battleground. Ferdinand's failure to complete the conquest of North Africa now brought a bitter revenge. The corsair leader Khayr ad-Din, known as Barbarossa, had made himself master of Algiers (1529) and acknowledged the suzerainty of the sultan of Constantinople. In 1535 Charles captured Tunis. He now seriously considered carrying the war into the eastern Mediterranean, even conquering Constantinople itself. But in 1538 Barbarossa with a Turkish fleet defeated Charles's Genoese admiral, Andrea Doria, at Préveza (western Greece), and in 1541 the emperor himself failed against Algiers. At the end of the reign, the balance of the two great naval powers in the Mediterranean, the Spanish and the Turkish, was still even.
Rival claims to Naples by the Aragonese and the Angevins (cousins of the ruling French house) also brought conflict with the French kings, against whom Charles fought four wars. His armies conquered Milan (northern Italy) and reduced most of the still independent Italian states to Spanish satellites.
In 1556, Philip II became king when on Jan. 16, 1556 Charles resigned in Philip's favour the kingdoms of Spain and the Spanish overseas empire. The court, which was at first in Toledo, was established in Madrid (1560).
In the Mediterranean the Spanish fleet was inferior to that of the Turks, and Philip had to remain on the defensive, even when the Turks were besieging Malta (1565). However, the Turks' failure to capture the island from the Knights of St. John, who had leased it from Charles V in his capacity as emperor, marked the end of their great offensive. Six years later the combined Spanish, Venetian, and papal fleets - in alliance the numerical equals of the Turks - virtually annihilated the Turkish fleet at Lepanto (1571). The strategic effects of this great victory were negligible, but its moral effects were immense. It confirmed the Spaniards in their chosen role as champions of Christendom and explains much of their continued willingness to support their king's religious and imperial policies, even in the face of ruinous costs and mounting disasters. After Lepanto, however, it became clear that the stalemate in the Mediterranean could not be broken. In 1580 Spain signed a truce with the Sublime Porte (Turkish government).
From about 1580 the Spanish government became convinced that the rebellion (1568-1609) and heresy in the Netherlands could not be crushed as long as the rebels received help from England and France. Philip began to give financial aid to the Holy League, the ultra-Catholic party in France. From 1586 he prepared the invasion of England. The Armada, which set sail from Lisbon in May 1588, numbered about 130 ships and nearly 30,000 men, bravely and not at all incompetently commanded by the Duke de Medina-Sidonia. But it had been set an impossible task: that of convoying the army under Alessandro Farnese, Duke de Parma, from the Netherlands to England in the face of a better-armed English fleet and without control of a single deepwater channel port. The defeat of the Armada was probably inevitable but not dishonourable.
Spanish intervention in France from 1590 was equally doomed to failure. The Duke de Parma, with his Spanish veterans, won great tactical victories, but Spain failed to prevent the succession of Henry of Navarre as Henry IV of France and the collapse of its ally, the Holy League, when Henry became Roman Catholic (1593).
Spain had gambled its own prosperity and its American treasure on a decisive victory over the heretics in western Europe and with it its own hegemony over the Continent, and it had failed. Shortly before his death, Philip II concluded the Treaty of Vervins (1598) with France. Yet, if Spain had failed in its highest ambitions, at the end of the 16th century it was still the greatest power in Europe.
1492, Columbus landed in the Caribbean. 1509-1510, Cardinal Ximenes in Morocco; 1519-1522, Magellan sailed round the world; 1519-1535, F. Cortez in Mexico; 1527, Pizarro in Peru. 1530s, Spaniards in La Plata and Chile; 1541, at the Amazon; 1565, in the Philippines.
Religious life was dominated by the power of the Inquisition. The Jesuit Order was founded by St Ignatius Loyola, 1491-1556 (St Francesco Borgia, 1510-1572; St Francis Xavier in India, 1542-1548, died in Japan in 1552). St John of the Cross founded the Order of Barefoot Friars in 1568. In 1551, the military Orders of Romar, Crato and Aviz supported the king of Portugal. The mystics (Luis de Granada, St Peter of Alcántara, St Theresa [1515-1582]).
Spanish literature and art were now entering their greatest period. Morally and economically there were dark sides to the picture, but to the Spaniards the 16th and early 17th centuries have always been their "Golden Century."
Humanism was encouraged by the Catholic kings and Cardinal Ximenes (d. 1517), the founder of Alcalá university (1499). D. Hurtado de Mendoza collected ancient manuscripts and medals, wrote the Life of Lazarillo de Tormes (1535). The theatre: autos pastoriles by Juan del Encina (d. 1529) and Gil Vicente (d. 1536). Poetry: Garcilaso de la Vega (1503-1536), now regarded as the founder of modern Spanish poetry; Boscan (d. 1543). Writings on the arts: E. Diego de Sagredo, Medidas del Romano, illustrated by Biguerny (1526); C. de Villalón, Ingeniosa Comparación (1539).
Music in Spain: Juan del Encina, poet and musician; A. Cabezón (1510-1566) and his organ school are especially notable.