Constructing a diocese in a post-conquest landscape: a comparative approach to the lay possession of tithes

This article explores how territorial conquest and consolidation of Muslim-ruled lands in the medieval Iberian Peninsula influenced the restoration and growth of frontier episcopal sees through an analysis of tithing. In comparing two neighbouring dioceses in the Crown of Aragon, Tortosa and Lleida, restored following the same mid-twelfth-century expedition with similar privileges yet differing frontier conditions, the study finds that the ability of dioceses to develop parishes and impose episcopal privileges was limited by conditions on the frontier which in turn conditioned the course and progress of seigniorial and royal territorial consolidation. In the wake of conquest, bishops in both Tortosa and Lleida often negotiated with lay lords who seized tithes on their lands in order to found and foster parishes. As the dioceses succeeded in developing their lands and the border with Islam was pushed further afield, willingness to compromise on tithe collection and permit lay retention of episcopal and parish revenues accordingly faded away. While bishoprics on the Iberian frontier did face special challenges with tithing created or influenced by their territorial environments not witnessed in the interior of Christendom, the temporary deviations from canonical provisions necessitated by these special conditions did not usually result in enduring differences in episcopal tithing practices.