[2] He was a nephew of the governor of Portuguese India, Lopo Soares de Albergaria - who had traveled to the island of Ceylon at the end of 1517, with the purpose of building a fortress in Colombo, as ordered by King Manuel I.

He appointed to the position of captain of the sea António Miranda de Azevedo, who, like Silveira, was considered "a nobleman with a good name, as there were many at that time";[3] and in Colombo he also left 100 men in the garrison, with weapons, ammunition and supplies.

However, considering that the guarantees had been obtained under duress, as a direct result of the constant pressure applied by the Portuguese governor on the sovereign of Kotte, it is likely that João da Silveira and his garrison were well prepared to suffer attacks.

João da Silveira suspected that it was the King of Kotte himself who had asked for this military intervention by the Zamorim of Calicut; however, "because he did not have orders from the governor [of Portuguese India] to break with him, he responded with great dissimulation".

A few days later, Lopo de Brito arrived in Colombo, with a "new form of government" (that is, with the formal powers of captain), accompanied by 400 men, including masons and carpenters, with the main objective of advancing in the construction of the fortress.