He also encountered the Indian Ocean island of Mauritius in 1512, although he may not have been the first Portuguese explorer to do so; earlier expeditions by Diogo Dias and Afonso de Albuquerque along with Diogo Fernandes Pereira may have encountered the islands.

[1] He was ambassador from Portugal to the Holy See,[2] where he appealed to Pope Paul III for the coming of the first jesuits for the Portuguese missions in India, at request of King John III and Diogo de Gouveia.

His mission ended on 15 March 1540, when he travelled back to Portugal together with Francis Xavier.

Mascarenhas tried to resist, arguing with his age but the King forced him to accept the post.

Gonçalo Rodrigues to Ethiopia in order to determine whether Emperor Galawdewos would be receptive to receiving a Patriarch anointed by the Roman Catholic church.