In the Early Middle Ages (c. 476-1000 CE) and throughout the High Middle Ages (1000-1300 CE) and Late Middle Ages (1300-1500 CE). The Catholic Church made it clear that one could only attain salvation and eternal life by following the precepts of the Church, and one’s alternative was an eternity in the torments of hell or a limited, but almost equally unpleasant, stay in the fires of purgatory where one’s sins were burnt away. Heaven, hell, and purgatory were regarded as absolute certainties after
death and, since the Church made all the rules regarding where a soul would wind up, people were forced to accept the clergy’s atrocious behavior.
The Christian mass was recited in Latin, the
Bible was in Latin, and prayers such as the Our Father and Hail Mary were taught to parishioners and memorized in Latin – a language none of the peasantry and few of the nobility understood. Christ’s ministry, as recorded in the gospels of the Bible, was therefore the sole property of the clergy who claimed only the Church could rightly understand the intentions of the Christian god and interpret them for others.
Of course from there, was only a matter of time before the burning of heretics began.
You tell me what doctrine led to this state of affairs. I believe it was the church thinking it was the authority, not Christ and not scripture.