Aristotle and S.Thomas Aquinas seem to have been the favorite masters of his study.

In fact he refused the new lights of the humanists, and adhered to the ecclesiastical training of the schoolmen.

Already at the age of twenty we find him composing a poem in Italian on the Ruin of the World, in which he cries: 'The whole world is in confusion: all virtue is extinguished, and all good manners; I find no living light abroad, nor one who blushes for his vices.' His point of departure had been taken, and the keynote of his life had been struck.

The sense of intolerable sin that came upon him in Ferrara haunted him through manhood, set his hand against the Popes and despots of Italy, and gave peculiar tone to his prophetic utterances.
The attractions of the cloister, as a refuge from the storms of the world, and as a rest from the torments of the sins of others, now began to sway his mind.[1] But he communicated his desire to no one.

It would have grieved his father and his mother to find that their son, who was, they hoped, to be a shining light at the court of Ferrara, had determined to assume the cowl.