 Vincenzo Barbaro and Theodore de Aquis were just two of some who wrote biographies on the late saint.There are sources that suggest Pope Callixtus III either canonized or beatified him through verbal consent on 15 October 1457 but it is believed for the most part that Pope Sixtus IV approved the canonization in a papal bull signed on 31 May 1476.It is likewise believed that Pope Nicholas V beatified him in 1454.