Between the year 1405, when Bethencourt had just accomplished the colonization of the Canary Islands, and the year 1492, what had taken place? We will give a short sketch of the geographical enterprise of the intervening years. A considerable impetus had been given to science by the Arabs (who were soon to be expelled from Spain), and had spread throughout the peninsula. In all the ports, but more especially in those of Portugal, there was much talk of the continent of Africa, and the rich and wonderful countries beyond the sea. "A thousand anecdotes," says Michelet, "stimulated curiosity, valour and avarice, every one wishing to see these mysterious countries where monsters abounded and gold was scattered over the surface of the land." A young prince, Don Henry, duke of Viseu, third son of John I., who was very fond of the study of astronomy and geography, exercised a considerable influence over his contemporaries; it is to him that Portugal owes her colonial power and wealth and the expeditions so repeatedly made, which were vividly described, and their results spoken of as so wonderful, that they may have aided in awakening Columbus' love of adventure. Don Henry had an observatory built in the southern part of the province of Algarve, at Sagres, commanding a most splendid view over the sea, and seeming as though it must have been placed there to seek for some unknown land; he also established a naval college, where learned geographers traced correct maps and taught the use of the mariner's compass. The young prince surrounded himself with learned men, and especially gathered all the information he could as to the possibility of circumnavigating Africa, and thus reaching India. Though he had never taken part in any maritime expedition, his encouragement and care for seamen gave him the soubriquet of "the Navigator," by which name he is known in history. Two gentlemen belonging to Don Henry's court, Juan Gonzales Zarco, and Tristram Vaz Teixeira had passed Cape Nun, the terror of ancient navigators, when they were carried out to sea and passed near an island to which they gave the name of Porto-Santo. Sometime afterwards, as they were sailing towards a black point that remained on the horizon, they came to a large island covered with splendid forests; this was Madeira. [Illustration: Prince Henry of Portugal--"The Navigator."] In 1433, Cape Bojador, which had for long been such a difficulty to navigators, was first doubled by the two Portuguese sailors, Gillianes and Gonzales Baldaya, who passed more than forty leagues beyond it.