In this chapter I trace the evolution of juristicthought regarding the proper locus of supremeauthority. I do this by exam¬ining how an ideaintroduced in the in􀀀uential papal decretal Per venerabilem wasreceived, re-worked, and re-interpreted over thecourse of the thirteenth century, in the processgenerating a concept of speci􀀀cally regnal sovereignty—a conceptthat would be taken up by the intellectualprotagonists in the con􀀀ict between Boniface andPhilip, and that would provide John of Paris with animportant element of his theory of sovereignty atthe turn of the fourteenth century.

Per venerabilem was apapal decretal that nominally dealt with the pope'spower to legitimize illegitimate children, not sothat they could enter holy orders (which wasestablished precedent), but so that they couldinherit property. The proximate cause for thetransmission of this decretal was a petition fromCount William of Montpellier requesting thatInnocent legitimize the children born of hismistress. Ordinarily, the count would have submittedthis petition to his temporal superior, the king ofFrance. In this case, however, William did not wantto compromise his defacto independence from the French crownby formally submitting such a petition; nor did hewish to undermine Montpellier's close commercial anddiplomatic relations with the Spanish kingdom ofAragon by formally acknowledging his vassalage tothe king of France. Having no other option, heappealed to Innocent, recalling in his petition thatthe pope had already legitimized the children of theillicit union of King Philip Augustus and Agnes ofMeran.

In response to this appeal, in 1202, Pope Innocent IIIissued Pervenerabilem. This decretal was structuredaround two basic lines of argumentation. Narrowly,it dealt with the speci􀀀cs of William's plea.Citing a number of factual and legal di􀀀erencesbetween William's case and that of Philip Augustus,Innocent rejected William's request outright. Butthat was not the end of the matter. More broadly,Per venerabilem madethe case that, although William's speci􀀀c plea wasfound wanting, the pope nevertheless possessed thegeneral right to decide such issues—that is, to actin temporal matters