This article demonstrates our methodology for studying the process of intra-Catholic confessional affiliation during the schism that occurred in the Catholic Church in the eighteenth-century Dutch Republic. The schism resulted in the remarkable fact that the Republic, a Protestant state, became home to two competing Catholic Churches, the Roman Catholic Church and the Roomsch-Katholieke Kerk der Oud-Bisschoppelijke Cleresie (​​OBC Church). In order to understand the choices made by laypeople for one of the two Catholic Churches, we created a dataset based on the baptisms and marriages taking place in two mission stations that were part of the OBC Church in the cities of Utrecht and Leiden. The data was ingested into a specifically designed graph database – connecting people, events (baptism and marriages), and places (churches and secular courts) – that enabled us to study the people who participated in events in the Catholic Churches as well as their roles at these events. In addition, we constructed ... : Journal of Historical Network Research, Vol. 10 No. 1 (2024): Regular Issue ...