{181} At last, in 1535, under the pressure of an invasion by Humáyún, Bahádur Sháh allowed the Portuguese to erect a fortress in Diu and to garrison it with their own troops. The fortress was rapidly and solidly built, and Bahádur Sháh and Nuno da Cunha signed a treaty of alliance. Such an alliance was not likely to last, and the murder of Bahádur Sháh in 1537, which took place on his return from visiting Nuno da Cunha on board his ship, caused a cry of treachery to be raised. It seems absolutely certain that the death of the King of Gujarát was due to a misunderstanding, but none the less friendship was owing to it replaced by bitter enmity. The fortress was not completed a moment too soon, for in 1538 the Turkish fleet, under Suláimán Pasha, after taking Aden by a stratagem, blockaded Diu by sea. Muhammad III, the nephew and successor of Bahádur Sháh, then besieged the place by land. 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 {182} 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.