At some point afterwards, and before 1522, Quintana became the Chaplain in King Charles V's retinue, and he started participating as a theologian in special royal assignments, such as the trials against the Protestant Probst and Grapheus.
[2] Quintana kept traveling with the royal retinue, and during the 1530s he kept being assigned to take part in additional royal religious decisions, clearly aimed at containing (and also repressing) theological ideas that would not be in agreement with the Catholic faith, which King Charles wanted to be preeminent: in 1525 he participated in the Edict against the Alumbrados, in 1526 in the Edict against the moriscos from Granada, and in 1527 was one of the experts who attended the Conference of Valladolid, in order to judge Erasmus's theological ideas.
And it also seems Quintana could have known the young Servetus while he was a studying in the Latin Grammar Studium of Sariñena near 1520, whose head was mosén Domingo Manobel.
[4] In 1530, shortly after Pope Clement VII crowned Charles V in Bologna, Dr. Juan de Quintana became the Emperor's Confessor and participated in the Diet of Augsburg, where he met and discussed theological issues with Philip Melanchthon.
Juan de Quintana was also named Lord of the village of Sipán (Huesca), and came back to Spain with the emperor in 1533, for the celebration of the Corts of Monzón.