But Henry returned from North-West Africa with perhaps a still greater prize—increased knowledge of the Dark Continent and a fixed determination to explore further a land which he now knew to be no mere sandy and unfertile desert. To this work he devoted the next forty-five years, without a shadow of turning, since political events might hamper but could not weaken his purpose, merely delaying the promised end.

It is often asked what was his object, as though the wish to win fresh knowledge, to acquire new territory for his country, and glory and riches, and to extend the Christian faith were unaccountable or unworthy aims. Rather we cannot wonder that the discoveries became the absorbing passion of his life, so that he has been blamed for his lukewarm intervention in contemporary politics and his weak defence of his brother, the Duke of Coimbra.

On the discoveries as Grand Master of the Order of Christ he spent its princely revenues, and in 1418, retiring from the Court, he settled on the Sacred Cape, or Sagres, now Cape St. Vincent. His palace and observatory soon drew a village round it, known as Terça Naval, or the Villa do Infante (Princestown). Here, as Governor of Algarve, he spent the greater part of his life, fitting out ships in Lagos harbour, welcoming travellers, poring over maps brought to him by Prince Pedro and others from their travels, observing the heavens, and watching for the return of his ships.

His keenness was not inconsistent with a certain shyness and reserve. He was a student prince, but less literary and more scientific than his brothers. All day, and often far into the night, he would be at work, an energetic hermit such as the Middle Ages had not known. His eyes in the intensity and even fierceness of their glance repelled the timid, but they also had the far-away look as of one watching and dreaming, while his firm lips and jaws were those of one planning and willing. His iron will and self-discipline curbed his equally strong temper and impatient eagerness, so that when most moved to anger he would merely say, like an Irishman, “I leave you to God.”

Courageous and persistent, he prepared all his schemes with the utmost thoroughness, and all the help that science could afford, and he carried them out with unfaltering resolution. All through his life he acted up to his French motto, Talent de bien faire, which we may translate by the “love of useful glory” to which, according to the poet Thomson, he roused mankind. And if we do not sit cowering before the unknown on all sides it is to Prince Henry and a few men of similarly keen intellect and stout will that we owe it.

It must not be thought that he met with no opposition, apart from the great difficulties that naturally beset all discoverers and innovators. On the one hand, the perils of navigating down the coast of Africa were considered insurmountable, and, on the other, the gains to be derived from it were held to be nugatory. It was not till the first slaves and the first gold arrived that men began to realise thoroughly that Prince Henry was something more than an empty dreamer. No one with less faith, a faith based both on religion and science, would have persevered, as Prince Henry persevered, in face of the slight support at first given by public opinion and the slight success obtained. But, although there were many disappointments and progress was slow, the mysteries of the African coast did gradually recede before his persistency, as year after year he sent out ships with definite instructions based on his maps and scientific knowledge.

The death of King João I in 1433 did not seriously interfere with his plans; his brother Duarte gave him every possible support, and the expedition against Tangier in 1437 was not an interruption but rather one aspect of his life-work. Indeed, he was the leading spirit of the enterprise. He and his younger brother, Fernando, obtained from King Duarte the consent for which they had ceased to hope from their father; but Duarte at first, and Pedro throughout, were opposed to the expedition. It set out in August, and the little army of some six thousand men disembarked at Ceuta, and, without waiting for the ships to return to Portugal for reinforcements, marched to attack Tangier.

Failing to take the place by storm, the princes settled down to blockade it. The danger of such a course was obvious, but even when the Moors, who trooped down from the hinterland, outnumbered the Christian force by twenty to one they were driven back in a series of magnificent attacks. But the Moorish host continued to grow by scores of thousands daily, and in the second week of October it became apparent even to the fiery heart of Prince Henry that he was embarked on a hopeless enterprise.

The siege was raised and the small army attempted to regain their ships. Henry with the cavalry protected their retreat. But the cowardice of some, the treachery of others, and the overwhelming number of the enemy proved too much for his splendid defence, and on October 15 he was forced to come to an agreement with the enemy. By this capitulation the Portuguese were to be allowed to re-embark without their arms, Ceuta, their twenty-two years’ possession, was to be given up, and Prince Fernando, with certain other hostages, was to remain in the hands of the enemy until the Portuguese should have evacuated the town.

Prince Henry, in his despair, fell ill at Ceuta and afterwards retired to Sagres. He would not give up Ceuta, and he could not save Fernando otherwise. King Duarte, confronted by the same cruel alternative, succumbed to grief and illness at Thomar in the following year.