The relationship between episcopal genealogy and ideology in the Roman Catholic Church

Abstract: In this study we investigate how hierarchical structures within the Roman Catholic Church shape the ideological orientation of its leadership. The full episcopal genealogy dataset comprises over 35,000 bishops, each typically consecrated by one principal consecrator and two co-consecrators, forming a dense and historically continuous directed network of episcopal lineage. Within this broader structure, we focus on a dataset of 245 living cardinals to examine whether genealogical proximity correlates with doctrinal alignment on a broad set of theological and sociopolitical issues. We identify motifs that capture recurring patterns of lineage, such as shared consecrators or co-consecrators. In parallel, we apply natural language processing techniques to extract each cardinal's publicly stated positions on ten salient topics, including LGBTQIA+ rights, women's roles in the Church, liturgy, bioethics, priestly celibacy, and migration. Our results show that cardinals linked by specific genealogical motifs, particularly those who share the same principal consecrator, are significantly more likely to exhibit ideological similarity. We find that the influence of pope John Paul II persists through the bishops he consecrated, who demonstrate systematically more conservative views than their peers. These findings underscore the role of hierarchical mentorship in shaping ideological coherence within large-scale religious institutions. Our contribution offers quantitative evidence that institutional lineages, beyond individual background factors, may have an impact on the transmission and consolidation of doctrinal positions over time.