In 1432 the University of Salamanca and King John II of Castile sent him as their representative to the Council of Basle, where he was one of the ablest defenders of the superiority of the council over the pope.
In 1432, the University of Salamanca and King John II of Castile selected him as their representative to the Council of Basel, where he played a key role in arguing for the council's dominance over the papacy.