Duarte doubted of the justice of the war, and referred the question to the Pope, who decided against it; but the answer came too late, the preparations were made, and the Infantes Henrique and Fernando took the command. Henrique was a most enlightened prince, a great mathematician and naval discoverer, but he does not appear to have made good use of his abilities on the present occasion; for, on arriving at Ceuta, and reviewing the troops, they proved to have but 8,000, instead of 14,000, as they had intended. Still they proceeded, Henrique by land and Fernando by sea, and laid siege to Tangier, which was defended by their old enemy, Zala ben Zala. Everything was against them; their scaling ladders were too short to reach to the top of the walls, and the Moors had time to collect in enormous numbers for the relief of the city, under the command of the kings of Fez and Morocco. The little Christian army was caught as in a net, and, after a day's hard fighting, saw the necessity of re-embarking. All was arranged for this to be done at night; but a vile traitor, chaplain to the army, passed over to the Moors, and revealed their intention. The beach was guarded, and the retreat cut off. Another day of fighting passed, and at night hunger reduced them to eating their horses. It was necessary to come to terms, and messengers were sent to treat with the two kings. The only terms on which the army could be allowed to depart were that one of the Infantes should remain as a hostage for the delivery of Ceuta to the Moors. For this purpose Fernando offered himself, though it was exceedingly doubtful whether Ceuta would be restored; and the Spanish poet, Calderon, puts into his mouth a generous message to his brother the King, that they both were Christian princes, and that his liberty was not to be weighed in the scale with their father's fairest conquest. Henrique was forced thus to leave his brave brother, and return with the remnants of his army to Ceuta, where he fell sick with grief and vexation. He sent the fleet home; but it met with a great storm, and many vessels were driven on the coast of Andalusia, where, by orders of the King, the battered sailors and defeated soldiers were most kindly and generously treated. Dom Duarte, having in the meantime found out with how insufficient an army his brothers had been sent forth, had equipped a fresh fleet, the arrival of which at Ceuta cheered Henrique with hope of rescuing his brother; but it was soon followed by express orders from the King that Henrique should give up all such projects and return home. He was obliged to comply, but, unable to look Duarte in the face, he retired to his own estates at the Algarve.