Partibus

Partibus is a Latin word-form used chiefly as the ablative or dative plural of pars, meaning “parts,” “regions,” or “lands.” In general Latin usage it appears in phrases describing portions of territory or areas within a larger domain.

The most notable use in English-language ecclesiastical writing is in partibus infidelium, literally “in the lands of the unbelievers.” This formulation was historically employed to designate dioceses that existed in name but lacked a stable, real territorial governance. Such sees were assigned to bishops as titular sees, allowing them to hold episcopal rank without exercising jurisdiction over a current, physical diocese. The practice arose in late antiquity and continued through the medieval and early modern periods, adapting to changing geopolitical contexts.

Related phrases include in partibus orientis (in the lands of the East), which similarly signified a non-local or auxiliary status for a see or mission presence. In broader Latin texts, partibus appears as a generic marker of territorial portions within a description of geography, law, or administration.

In contemporary usage, the term partibus infidelium remains a historical reference point in studies of church structure and the history of missionary activity. The concept of titular sees continues to exist in limited form within the Catholic Church, though the specific administrative practice has evolved over time.

In summary, partibus serves as a grammatical vehicle for denoting territories or portions in Latin, with its most enduring significance arising from its association with the historic system of titular sees in the Catholic Church.