In his youth, he served as a page of Queen Eleanor, consort of King John II, alongside Magellan.
[3] Having been rejected by the Portuguese king, Faleiro and Magellan presented their proposal to the Casa de Contratación, which managed expeditions on behalf of the crown.
[5] Faleiro boasted that with his expertise in navigation and astronomy, he would be able to prove that the Spice Islands were situated on the Spanish side of the line of Tordesillas.
Sebastian Alvarés, a Portuguese spy reporting to King Manuel, wrote that Faleiro was "like a man deranged in his senses".
[10] Other sources state that Faleiro chose to remain behind after performing a horoscope reading indicating that the voyage would be fatal for him.
In his duties as the expedition's astronomer and astrologist, Faleiro was replaced by the Spanish cosmographer Andrés de San Martín.