Definition
In canon law, compaternitas denotes a form of spiritual relationship (cognatio spiritualis) arising from the sacrament of baptism. The relationship bound together the baptized person, the baptizing priest, the godparents, and the natural parents of the baptized into a recognized quasi-familial bond recognized by ecclesiastical authority. Because canon law treated this spiritual kinship as analogous to natural blood relation, compaternitas carried legal consequences within the Church's jurisdiction — most notably as a bar to marriage and, historically, as a ground for divorce or annulment between parties who discovered such a relationship existed between them.
Why It Matters in Research
This is a term researchers will encounter almost exclusively in ecclesiastical and medieval sources. Its primary legal significance operated entirely within the canon law system, meaning it appears in ecclesiastical court records, canonical treatises, and Church council proceedings rather than in common law reporters or secular statutes.
Several research traps are worth flagging. First, compaternitas is a subset of the broader canonical category of cognatio spiritualis (spiritual cognation). Researchers searching for marriage impediments in historical Church sources should search both terms, as authors used them interchangeably or at different levels of specificity. Second, the divorce or annulment ground it created is easily misread by researchers accustomed to modern divorce law — the canonical "divorce" here is more precisely a declaration of nullity, not a dissolution of valid marriage. Third, the relationship it describes has no surviving legal equivalent in modern secular law in any common law jurisdiction; researchers encountering the term in any post-19th-century source should treat it as a historical reference.
The term surfaces in English legal sources primarily through Bracton, who acknowledged canon law impediments in his treatment of marriage and legitimacy. Researchers working with Bracton's De Legibus et Consuetudinibus Angliae on questions of marital status or legitimacy should note that Bracton's treatment of spiritual relationships reflects ecclesiastical rather than common law doctrine.
Historical Dictionary Support
All three source dictionaries agree on the core definition: a spiritual relationship created by baptism, classified within canon law under the broader heading of cognatio spiritualis. Burrill provides the most useful detail, citing Heineccius's Elementa Juris Civilis (lib. 1, tit. 10, § 161) and Bracton (fol. 298b) as primary authorities, and explicitly identifying compaternitas as one of the grounds of divorce under canon law. The two editions of Black's are essentially identical and add nothing beyond the core definition.
What all three sources omit is the structural detail of who exactly the relationship connected. Canon law doctrine on cognatio spiritualis distinguished among the godparent-godchild bond, the bond between godparent and natural parent (which is the more precise referent of compaternitas as a term — "co-fatherhood" or "co-parenthood" in the spiritual sense), and related sub-categories. The dictionary entries collapse these distinctions. Researchers needing precision on how ecclesiastical courts applied the impediment should consult the canonical sources directly, particularly through Heineccius and the Decretum of Gratian.
Jurisdictional Note
Compaternitas as an operative legal concept belonged entirely to ecclesiastical jurisdiction. In England, it would have been applied by Church courts prior to and during the Reformation period. Following the English Reformation and the eventual transfer of matrimonial jurisdiction, the concept lost practical legal effect in English law. It retains no operative role in any modern common law jurisdiction.