Throughout the Early Middle Ages, the Catholic Church generally opposed the use of torture during criminal proceedings. This is evident from a letter sent by Pope Nicholas I to Khan Boris of the Bulgars in AD 866, delivered in response to a series of questions from the former and concerned with the ongoing Christianisation of Bulgaria. "Ad Consulta Vestra" (as entitled in Latin) declared judicial torture to be a practice that was fundamentally contrary to divine law. The Pontiff made it a point of incontrovertible truth that, in his own words: "confession a crime should be spontaneous, not compelled, and should not be elicited with violence but rather proferred voluntarily". He argued for an alternative and more humane procedure, in which the accused person would be required to swear an oath of innocence upon the "holy Gospel that he did not commit crime which is laid against him and from that moment on the matter is be put at an end". Nicholas likewise stressed in the same letter that "those who refuse to receive the good of Christianity and sacrifice and bend their knees to idols" were to be moved towards accepting the true faith "by warnings, exhortations, and reason rather than by force," emphasising to this end that "violence should by no means be inflicted upon them to make them believe. For everything which is not voluntary, cannot be good".