The FACT that inquests (AN inquisition) took place, or that they were formed by local and some times papal command, is not indispute. The concept of the Medieval Inquisition as a large all pervasive organization is however a myth.
You are missing my point. Although the Inquisition may have started more informally and/or locally, at some point it did become institutionalized as an official congregation within the Vatican curia.