Renaissance humanists tended to disregard medieval scholasticism. But most of humanist anti-scholasticism was directed against late medieval exaggerations in the areas of conceptualism and nominalism. Therefore, it is interesting to find out whether these humanists had a precise and justified view of medieval philosophers and theologians, and especially of Thomas Aquinas. Two writings of humanists, which expressly deal with Aquinas, namely the Encomium S.~ThomaeAquinatis by Lorenzo Valla (1457) and the Opus aureum in Thomistas (1490s) by Johannes Baptista Spagnoli Matnovano give witness of the humanist philosophical approach to the saint and teacher of the Church. A look at these two treatises discloses some basic features of humanist thought, and ex negativo of the importance and specific value of Thomas Aquinas in the post-medieval culture. They also show samples of how monopolizing one authority might endanger its very acceptance.