From the sixth century on, the Catholic Church denied formal funeral rites to people who died by suicide. One touchstone for medieval Christian understandings of suicide was the story of Judas, who, at least according to the Gospel of Matthew, hanged himself after feeling remorse for betraying Jesus. In medieval Christian thought, this narrative connected the act of killing oneself with the sin of despair—the loss of faith in God and divine forgiveness.
‎ Between 1000 and 1200, the secular justice system began to condemn suicide more harshly as well. In the twelfth century, many parts of Europe began defining self-murder as a felony, in part because it deprived an individual’s feudal lord of his possession. Depending on the specific time and place, the possessions of someone who had died by suicide could be seized by a lord or by the monarchy. In early fifteenth-century France, the law called for the house of a suicide victim to be pulled down, his fields burned, and his woods felled.
‎ Not only did laws demand that the wealth of someone who died by suicide be seized, but they often called for the “torture” of their bodies.

(Gershon, 2021)

Enough of it that the ruling clerical and monarchical class felt threatened by their perceived material losses to outlaw it.

Gershon, L. (2021, March 22). Why Suicide Was a Sin in Medieval Europe. JSTOR Daily.