Losing his parents in infancy, he was brought up by his sister Filipa de Vilhena and her husband, the Marquis of Távora.

He used to say that God had given him the great grace of unsuitability for government — apparently basing this on a certain want of tact in dealing with human weakness.

The expedition sent to avenge Silveira's death never reached its destination, while his apostolate came to an abrupt end from a want of missionaries to carry on his work.

A cause for Silveira's beatification was formally opened in 1629, and he was granted the title Servant of God in the Catholic church.

[1] H. Rider Haggard would base the fictional character, José Silvestre, on Silveira in his 1885 novel, King Solomon's Mines.