Having filled the post of nuncio in England and Spain, he served successive popes as adviser in matters pertaining to heresy and reform.
The papal nuncio at Prague, in particular, appears for a time to have obtained great influence over the king.
The pope had repeatedly used the rich northern benefices to reward members of the Roman curia, and towards the close of the year 1516 he sent the grasping and impolitic Arcimboldi as papal nuncio to Denmark to collect money for St Peter's.
Leo sent a new nuncio to Copenhagen (1521) in the person of the Minorite Francesco de Potentia, who readily absolved the king and received the rich bishopric of Skara.
Xavier complied, merely waiting long enough to obtain the pope's benediction, and set out for Lisbon, where he was presented to the king, and soon won his entire confidence, attested notably by procuring for him from the pope four briefs, one of them appointing him papal nuncio in the Indies.