Sigillvm: corpus of Portuguese Seals aims in a primary stage at the inventorying, cataloguing, organising and processing of Portuguese medieval secular clergy seals. By secular clergy one means the aggregation of clergy members who were not included in any monastic order, performing their duties in the laic world, as members of the clergy of cathedrals and collegiate churches or parish priests.
During the Middle Ages, Portugal sustained nine dioceses, some restored from former Visigoth sees, others born anew through the process of the Reconquista. The following were included in this ecclesiastic geography: the dioceses of Braga (restored in 1071), Coimbra (in 1080), Oporto (in 1112/1114), Lisbon, Viseu and Lamego (in1147), Évora (in 1166), Guarda (in 1199) and Silves (in 1253).