[Footnote 378: My chief authorities for the achievements of Prince Henry and his successors are the Portuguese historians, Barros and Azurara. The best edition of the former is a modern one, Barros y Couto, _Decadas da Asia, nova edicao con Indice geral_, Lisbon, 1778-88, 24 vols. 12mo. I also refer sometimes to the Lisbon, 1752, edition of the _Decada primeira_, in folio. The priceless contemporary work of Azurara, written in 1453 under Prince Henry's direction, was not printed until the present century; Azurara, _Chronica do Descobrimento e Conquista de Guine_, Paris, 1841, a superb edition in royal quarto, edited by the Viscount da Carreira, with introduction and notes by the Viscount de Santarem.] [Footnote 379: Partly, perhaps, because Mela was himself a Spaniard, and partly because his opinions had been shared and supported by St. Isidore, of Seville (A. D. 570-636), whose learned works exercised immense authority throughout the Middle Ages. It is in one of St. Isidore's books (_Etymologiarum_, xiii. 16, apud Migne, _Patrologia_, tom. lxxxii. col. 484) that we first find the word "Mediterranean" used as a proper name for that great land-locked sea.] [Sidenote: The Sacred Promontory.] Filled with such lofty and generous thoughts, Prince Henry, on his return from Morocco, in 1418, chose for himself a secluded place of abode where he could devote himself to his purposes undisturbed by the court life at Lisbon or by political solicitations of whatever sort. In the Morocco campaign he had won such military renown that he was now invited by Pope Martin V. to take chief command of the papal army; and presently he received similar flattering offers from his own cousin, Henry V. of England, from John II. of Castile, and from the Emperor Sigismund, who, for shamefully violating his imperial word and permitting the burning of John Huss, was now sorely pressed by the enraged and rebellious Bohemians. Such invitations had no charm for Henry. Refusing them one and all, he retired to the promontory of Sagres, in the southernmost province of Portugal, the ancient kingdom of Algarve, of which his father now appointed him governor. That lonely and barren rock, protruding into the ocean, had long ago impressed the imagination of Greek and Roman writers; they called it the Sacred Promontory, and supposed it to be the westernmost limit of the habitable earth.[380] There the young prince proceeded to build an astronomical observatory, the first that his country had ever seen, and to gather about him a school of men competent to teach and men eager to learn the mysteries of map-making and the art of navigation. There he spent the greater part of his life; thence he sent forth his captains to plough the southern seas; and as year after year the weather-beaten ships