Quote from : Why Catholics are Right Book

In 1231, Pope Gregory ordered the Dominicans to take charge of papal courts and decisions and so prevent mob rule and guarantee that the accused received a fair trial and the right of defence. This was the foundation of the Inquisition, and it was a move to organize, control, and limit violence, disruption, and division. Of course, it often failed and even achieved the opposite of its stated and original purpose, but it's surprising how often in an age of casual and brutal violence a relative moderation and legality was achieved. Civil law was far harsher than canon law, demanding confiscation of a heretic's property and usually death, something the Church had tried to prevent for generations.