Papal bull “Numquam Dubitavimus” issued by Sixtus IV [Aragon] [Unconfirmed]
Commentary from other sources:
1) “Numquam dubitavimus by Sixtus IV in 1482, empowered Ferdinand of Aragon to appoint inquisitors to extirpate heresy and to prevent Jewish practices among those who had been converted to Christianity.”
Solomon Grayzel: “Bulls, Papal.” Online article