It is interesting to speculate how and when Columbus first conceived an idea of such stupendous importance. It was doubtless not until he was a mature and experienced man, who had become not only a skilled sailor, but one familiar with what other sailors had done. The Madeiras and the Azores had been discovered more than a century. Prince Henry, the Navigator (that great patron of early exploration), was sending his crews down the west coast of Africa,--for at that time it was not even known what the lower half of Africa was. These expeditions were a great help to Columbus as well as to the world's knowledge. It is almost certain, too, that when he was in Iceland he must have heard something of the legends of the Norse rovers who had been to America. Everywhere he went his alert mind caught some new encouragement, direct or indirect, to the great resolve which was half unconsciously forming in his mind. About 1473 Columbus wandered to Portugal; and there formed associations which had an influence on his future. In time he found a wife, Felipa Moniz, the mother of his son and chronicler Diego. As to his married life there is much uncertainty, and whether it was creditable to him or the reverse. It is known from his own letters that he had other children than Diego, but they are left in obscurity. His wife is understood to have been a daughter of the sea-captain known as "The Navigator," whose services were rewarded by making him the first governor of the newly discovered island of Porto Santo, off Madeira. It was the most natural thing in the world that Columbus should presently pay a visit to his adventurous father-in-law; and it was, perhaps, while in Porto Santo on this visit that he began to put his great thoughts in more tangible shape.