The first and second decretal waves, c. 400 and c. 1200, both responded to unresolved complexities arising from the evolution of separate social systems. In the standard gloss on Gratian, ‘Gloss II’, decretals from the two ages are brought into conjunction. Innocent I’s ruling about pagan marriages was generating thoughtful discussion eight centuries after his death. The standard gloss discusses it together with a decretal of Innocent III. Between Innocent I and Innocent III, the ‘Pauline Privilege’ system emerges clearly into view, taken for granted by Innocent III after an evolution at which for want of evidence we can only guess. How to integrate the earlier Innocent’s ruling with the ‘Pauline Privilege’ system? This is an example of how the horizon of reflection about a text can be enlarged over time, without losing contact with the original meaning, as it is applied in new context and to complex scenarios not originally envisaged.

Episcopal elections furnish another example of the enlargement of legal meaning in the course of its application to new states of affairs. The conversation started by Celestine I in 428 when he sent Nullus invitis to Southern Gaul was continued with reference to situations and conditions different from those of the Roman Empire. Not in all respects. Just as monks from late Roman Lérins were leapfrogging over local clerics to bishoprics in Gaul, friars were being appointed as bishops in the thirteenth century. But clerical communities around late Roman bishops resembled neither the gamut of clergy spread over large thirteenth-century dioceses, nor the canons of thirteenth-century cathedrals. The slow transformation of the Western diocese and the Investiture Contest left a legacy of uncertainty about how to elect a bishop. In the thirteenth century, the efforts to create a transparently rational system for larger and more impersonal units were complicated both by uncertainties of the ‘greater and sounder part’ rule, and by the complexities of the concrete situations revealed by ‘modern’ rulings, from the second age of decretals, which glossators bring to bear on Celestine I’s decision.

The strange and interesting bigamia rule remained a constant from the fourth century on, but the social worlds to which it was applied were different. A high proportion of the (very numerous) thirteenth-century clerics in minor orders did not have much to do with the clerical world, whereas their late Antique counterparts were presumably more or less integrated into the tight community around the city’s bishop. In the thirteenth century, the bigamia rule enabled popes and kings to deny clerical privileges to phony clergymen who enjoyed fiscal and judicial immunities, even though those clerics were supported by bishops whose power and profits they enhanced.