Antonio da Silveira, who had been left by Nuno da Cunha as Captain of the fortress, defended it nobly. Brilliant are the feats of gallantry recorded by the Portuguese chroniclers on the part not only of the soldiers but of aged men, boys, and women. The siege lasted many months, during which Nuno da Cunha was succeeded in September 1538 by Dom Garcia de Noronha, Albuquerque's nephew, who had been sent out from Portugal as Viceroy. This experienced officer managed to introduce reinforcements into the fortress in small boats which slipped between the great Turkish galleys. Every assault was repulsed, and in November 1538 Suláimán Pasha and Muhammad III abandoned the siege. It does not detract from the glory of Silveira's defence that its final success was mainly due to dissensions among the besiegers. Each of the Muhammadan commanders blamed the other; the King of Gujarát began to fear that the Turkish admiral would attack him, and it was with a sense of relief that he, as well as the Portuguese, saw Suláimán sail away to Arabia.

It was a melancholy fact that Nuno da Cunha was unable to witness the success of his brother-in-law, Silveira. In spite of his great services he, like his relative Affonso de Albuquerque, whom he resembled in his wide views and his personal disinterestedness, was slandered at the Court of Lisbon. He had taken harsh measures against embezzling officials and insubordinate captains, and during his ten years of government he made numerous enemies. These men persuaded the King that Nuno da Cunha was making a large fortune, when really he was spending his private property for the public service; and, in spite of the arguments of old Tristão da Cunha, Dom Garcia de Noronha was ordered to send the greatest Portuguese Governor of India since Albuquerque home in custody. On his way home Nuno da Cunha died at sea on March 5, 1539, in the fifty-second year of his age, and his last words, when his chaplain asked what should be done with his body, were: 'Since the will of God is that I should die at sea, let the sea be my grave; for since the land will not have me why should I leave my bones to it.' Nuno da Cunha's establishment of the Portuguese at Diu was the most important event since the conquest of Goa; in temper and in disposition he resembled his great relative; like Albuquerque, he was treated with ingratitude and died in disgrace.

Dom Garcia de Noronha did not rule long enough to affect the history of the Portuguese in India. He died at Goa on April 3, 1540, and was succeeded as Governor, not as Viceroy, by Dom Estevão da Gama, the second son of the famous navigator. The new governor was an experienced officer; he had been Captain of the Sea during his father's short viceroyalty in 1524; had made more than one voyage to India; and had acted for five years as Captain of Malacca.

The one remarkable event of his governorship was his expedition to the Red Sea. The repulse of Suláimán Pasha had been followed by his death in Arabia, but Suláimán the Magnificent did not intend to abandon his projects, and directed the equipment of a new fleet at Suez. In 1541 Dom Estevão da Gama entered the Red Sea. He was repulsed in an attack on Suez, but made a landing in the neighbourhood and a pilgrimage to the monastery of Mount Sinai, where he knighted some of his officers, including Dom Alvaro de Castro, the son of his most distinguished captain, Dom João de Castro. Before returning to India the Governor sent his brother, Dom Christovão da Gama, to escort a prelate, whom the Pope had nominated as primate of Abyssinia. But the Christian dynasty in that country was at this time hotly beset by the Muhammadans, and Dom Christovão was killed with his companions.

In the year 1542 Dom Estevão da Gama was succeeded as Governor by Martim Affonso de Sousa, who had shown ability in the exploration and settlement of the colony of Brazil. De Sousa's government of India was not very successful. His most notable achievement was a treaty with Ibráhím Adil Sháh, King of Bijápur, who promised to cede to the Portuguese the provinces of Bardes and Salsette adjoining the island of Goa in exchange for the surrender of a Muhammadan prince, Mir Ali Khán (Mealecan). But Martim Affonso de Sousa had neither the ability nor the authority to maintain his influence over his own captains, and King John III resolved to send to India a nobleman of military experience, who by his rank and his character should restore harmony in his Asiatic possessions.

The nobleman selected was Dom João de Castro, who was the intimate friend of the King's brother Dom Luis. With that prince he had served in the expedition against Tunis, where his conspicuous valour had won the admiration of the Emperor Charles V. He displayed courage, tact, and self-reliance, both in the relief of Diu and in the campaign of 1541 in the Red Sea. But it was for the purity of his personal character, the integrity of his life, and his absolute honesty that he was specially selected.

Enormous fortunes were being made in the East, and the usual abuses accompanied the rapid acquisition of wealth. Bribery and corruption in public life, gambling and immorality in private life had reached an alarming height, and though the Portuguese still exhibited the same valour and constancy in war as in the days of Albuquerque, they were now too apt to prefer private advantage to the good of the State. Dom João de Castro took out with him a powerful fleet and 2000 soldiers, and he was accompanied by two young sons, Dom Alvaro and Dom Fernão, who rivalled in the East the glory of the youthful Dom Lourenço de Almeida and of Albuquerque's young nephew Dom Antonio de Noronha.

Dom João de Castro reached Goa on September 10, 1545, and at once took over the charge of the government. He found himself face to face with two serious dangers; Ibráhím Adil Sháh of Bijápur was preparing to attack Goa, and Muhammad III of Gujarát was again besieging Diu. These were but symptoms of a general league which was in act of formation between all the sovereigns of the West of India against the Portuguese. In spite of the expostulation of the officials João de Castro refused to carry out the engagement made with the King of Bijápur by his predecessor. He declared that Mir Ali Khán had come to seek refuge at Goa, and that it would be a most dishonourable act to surrender him. The King of Bijápur at once sent an army to recover the provinces of Bardes and Salsette, which he had handed over, but Dom João de Castro marched out and inflicted a severe defeat on the Bijápur forces.

The situation at Diu was more threatening. A renegade Albanian, called by the Portuguese Coge Çofar (Khoja Zufar), had attained supreme influence at the Court of Muhammad III of Gujarát. He persuaded the King that it was most disgraceful for him to fail in capturing Diu. He collected the whole force of the kingdom and commenced the siege of the Portuguese fortress, with the declaration that he would die sooner than return unsuccessful. The Captain of Diu, Dom João Mascarenhas, showed the same constancy and valour as Antonio da Silveira. The garrison consisted of nearly the same soldiers, and the women once more distinguished themselves in the defence. The Governor made every effort to relieve the fortress. He first sent his son, Dom Fernão, who was killed, then his other son, Dom Alvaro, and eventually brought up all the forces he could collect in person. Coge Çofar was slain by a cannon-ball, and his successor, Rumecão, did not press the siege with the same vigour.