The difference between intention and execution has always been the bane of governments, and was particularly so for the medieval Church, relying as it did mainly on spiritual authority. The institution of the inquisition was an unusual attempt to create a new operational arm. When thinking about its development in Italy over the century from 1250 to 1350, I found Richard Kieckhefer's fundamental discussion of the office very useful in shaping my approach and helping to frame questions which would get the best out of the source material. It encouraged me to look closely at the inquisitor's staff, who they were and what they did, and it provided me with the fundamental question and theme. How far was the medieval inquisition a loose association of separate personal jurisdictions, rather than an institution functioning cohesively both over time and across regions?

Secondly, how the papal inquisition really interacted with its episcopal and secular partners after Innocent IV's imposition of a tripartite structure in 1252 is clearly a crucial issue. While much attention has been paid to the position as set out in manuals and consilia, the real details of daily relationships have been much less considered. Inevitably, we find a picture which diverges in many respects from what was contemplated in Ad extirpanda. And thirdly, the inquisitors’ relationship in practice with the mendicant orders, of which they were senior members but from whose control they were theoretically liberated, raises a host of issues which rapidly extend beyond their personal dilemmas of obedience into the economic role of the Church in the thirteenth and fourteenth centuries.

In exploring these major questions, other points were thrown up. In a study which aims to cover as much territory as this, there are also inevitably things which are missing or under-considered or could be set out differently. Some issues I was unable to resolve to my own satisfaction, though further work might bring rewards. But there are some broad conclusions which seem justifiable.

Richard Kieckhefer helpfully provides criteria by which to test his own hypothesis, the most important being his argument that there was no continuity in inquisition staffing. He accepts that permanent staff, especially inherited by one inquisitor from his predecessor, would be strongly suggestive of institutionalisation.