[Illustration: TWO SIDES OF THE ROYAL CHAPEL OF THE MONASTERY OF BATALHA. (PRESENT STATE.)]
On May 9, 1386, the Treaty of Windsor was signed by which the kingdoms of Portugal and England were declared to be united henceforth in the closest bonds of friendship and alliance; and it proved to be the corner-stone of the policy of the House of Aviz. On July 20, 1386, John of Gaunt reached Corunna with two thousand English lances and three thousand archers, accompanied by his wife Constance of Castile, and two of his daughters, Philippa and Catherine. He marched triumphantly through Gallicia; and at Oporto on February 2, 1387, the Anglo-Portuguese Alliance was sealed by the marriage of King John to Philippa, the daughter of John of Gaunt by his first wife, Blanche of Lancaster. This marriage was followed by another, that of Catherine, only child of John of Gaunt by Constance of Castile to Henry, Prince of the Asturias, and heir to the throne of Castile. These marriages settled the peace of the peninsula, for in concluding them, John of Gaunt abandoned his claims to Castile, and insisted as one of the conditions, on a truce between his two sons-in-law. This truce continued till 1411, when at last the title of John as King of Portugal was recognized, and peace between Castile and Portugal was solemnly declared.
King John "the Great" was now firmly seated on his throne; an effort of his half-brother Diniz, the younger son of Ines de Castro, to overthrow him in 1398, failed entirely, and foreign monarchs hastened to recognize his power. Through this hero, and the race of heroes who fought under him, the independence of Portugal was secured, and a new career opened before its people. The era of consolidation was over; the era of foreign discovery and of Asiatic conquests was to begin.
(_From his recumbent statue over his tomb at Batalha._)]
The reigns of John I., surnamed "the Great," and of his two successors, occupy nearly a century, during which Portugal was learning to become the greatest nation in Europe. It was the age of exploration and discovery, during which the acutest intellects and the most daring natures in Portugal were dreaming of a new route to India, and were endeavouring to discover it. It was an age of growth, abounding in statesmen, mariners, and chroniclers, who were to have their successors in the all too short but immortal period of Portuguese greatness, in such men as Alboquerque, Vasco da Gama, and Camoens. The history of these maritime explorations and discoveries, of the painful and slow progress down the western coast of Africa, and of the great schemes and efforts of Prince Henry "the Navigator," will form the subject of a separate chapter; but it is first expedient to study the history of the Portuguese people and monarchy at home during this period, and to see how, from the reign of John I., a new spirit appeared alike among the kings, and the merchants, and the soldiers, which was to culminate in the glories of the heroic age.