The Evolution of Canon Law

For centuries, Roman law functioned as the lex subsidiaria of the Catholic Church, providing the conceptual categories and technical vocabulary through which ecclesiastical norms were articulated. This reliance was not merely pragmatic but reflected a profound cultural assimilation, whereby Roman jurisprudence offered stability and legitimacy to the Church’s governance. Nevertheless, the decline of Roman law as a living system and the rise of modern nation states necessitated a new juridical approach. This article examines the transition from the organic absorption of Roman legal concepts to the formal mechanism of canonizatio legum civilium, the canonization of civil laws, by which the Church deliberately incorporated contemporary civil norms into its own legal framework. The study argues that the promulgation of the 1917 Codex Iuris Canonici marked a decisive rationalization of Church–State legal relations, replacing reliance on Roman law with a structured system of deferment to modern civil codes for secular matters. It further contends that the 1983 Code reaffirmed and consolidated this principle within the ecclesiological vision of Vatican II, ensuring that canon law remained sovereign yet adaptable. By tracing this evolution, the article highlights how canonizatio continues to serve as a mechanism of harmonization, enabling the Church to engage diverse civil jurisdictions while preserving its juridical independence.