In 1382 a powerful Spanish fleet besieged Lisbon. The defence of the city was entrusted to Nun’ Alvarez and his brothers. It was in late summer, _quando l’uva imbruna_, and parties from the fleet would land to gather grapes and other fruit. Nun’ Alvarez saw his opportunity and, leaving the city one night with some fifty horse and foot, lay in ambush in the vines by the bridge of Alcantara. The first boatload of twenty Spaniards to land was driven headlong into the sea, but a larger force came ashore and the Portuguese, seeing themselves outnumbered five to one, fled. Nun’ Alvarez, left alone, spurred his horse to a gallop and dashed into the midst of the enemy. His excellent armour stood him in good stead, but his lance was shattered, his horse cut down, and one of his spurs caught in the saddle as he fell. Thus disabled he still fought on, and then for very shame his followers turned to assist him. The first to come up was a Lisbon priest, afterwards Canon of Lisbon Cathedral. Nun’ Alvarez, hearing a few months later that the King was to engage the enemy between Elvas and Badajoz, proposed to his elder brother Pedr’ Alvarez, who had succeeded their father as Prior of Crato, that they should have a hand in the fighting. Pedro, who had orders to defend Lisbon and intended to obey them, refused, and, having previous acquaintance of Nuno’s methods, gave instructions that no armed persons should be allowed to leave the city. Nuno with a few attendants dashed past the guard at the gate and rode post-haste to Elvas. He was well received by the king, but again there was no fighting. Peace and the betrothal of Beatrice were celebrated in a banquet at Elvas. King Ferdinand was too ill to attend, but King Juan was present. Nun’ Alvarez, in his bitterness at seeing Portugal given over to Castille, for once forgot his manners. He and his brother Fernão, going in more leisurely than the rest, found all the tables crowded, and, unable to obtain a place, he pushed away the support from one of the tables, which went crashing to the ground, and calmly went out. King Juan remarked that he who so acted had a heart for greater things, but, in the words of the old chronicle, had they been Castilians he might have spoken differently. After King Ferdinand’s death Nun’ Alvarez, brooding over his country’s wrongs, keenly took the part of the young Master of Avis. He was not present at the murder of the Queen’s favourite, the Count Andeiro, but he approved the act, and when news of it reached him at Santarem he hastened to Lisbon to the Master of Avis.