On the inhospitable shores of southern Portugal, amid the "sadness of a waste of shifting sand, in a neighbourhood so barren that only a few stunted trees struggled for existence, on one of the coldest, dreariest spots of sunny Portugal," Prince Henry built his naval arsenal. In this secluded spot, far from the gaieties of Court life, with the vast Atlantic rolling measureless and mysterious before him, Prince Henry took up the study of astronomy and mathematics. Here he gathered round him men of science; he built ships and trained Portuguese sailors in the art of navigation, so far as it was known in those days. Then he urged them seawards. In 1418 two gentlemen of his household, Zarco and Vaz, volunteered to sail to Cape Bojador towards the south. They started off and as usual hugged the coast for some way, but a violent storm arose and soon they were driven out to sea. They had lost sight of land and given themselves up for lost when, at break of day, they saw an island not far off. Delighted at their escape, they named it Porto Santo and, overjoyed at their discovery, hastened back to Portugal to relate their adventures to Prince Henry. They described the fertile soil and delicious climate of the newly found island, the simplicity of its inhabitants, and they requested leave to return and make a Portuguese settlement there. To reward them, Prince Henry gave them three ships and everything to ensure success in their new enterprise. But unfortunately he added a rabbit and her family. These were turned out and multiplied with such astonishing rapidity that in two years' time they were numerous enough to destroy all the vegetation of the island. So Porto Santo was colonised by the Portuguese, and one Perestrello was made Governor of the island; and it is interesting to note that his daughter became the wife of Christopher Columbus. But the original founders, Zarco and Vaz, had observed from time to time a dark spot on the horizon which aroused their curiosity. Sailing towards it, they found an island of considerable size, uninhabited and very attractive, but so covered with woods that they named it Madeira, the Island of Woods. But although these two islands belong to Portugal to-day, and although Portugal claimed their discovery, it has been proved that already an Englishman and his wife had been there, and the names of the islands appear on an Italian map of 1351. [Illustration: AFRICA--FROM CEUTA TO MADEIRA, THE CANARIES, AND CAPE BOJADOR. From Fra Mauro's map, 1457.]