respublica Christiana

• rēs pūblica Chrīstiāna
• Chrīstiāna rēspūblica

First attested in Augustine of Hippo: "Omnium enim christianorum una respublica est" ("For there is one commonwealth of all Christians"), De opere monachorum (c. 400 C.E.), 23.33. In early medieval usage, used chiefly to refer to the Byzantine Empire. From c. 9th century applied to the dominion of Frankish kings and emperors in the West. Generalised to refer to the community of all Christian states in the 11th century, which became the predominant meaning from the High Middle Ages on.

rēspūblica Chrīstiāna f sg (genitive reīpūblicae Chrīstiānae); fifth declension (Ecclesiastical Latin)

1. Christendom, the Christian nations as a political community.
   • 1552, Council of Trent, Sacrosancti Concilii Tridentini decreta et canones, Sessio XVI:

     caputque attollere inciperet profligata antea, & afflicta Respublica Christiana

     and the Christian commonwealth, so abandoned and afflicted before, began to lift up its head

2. (Medieval Latin) The Christian empire, i.e. the Byzantine Empire or the Holy Roman Empire.

Fifth-declension noun with a first-declension adjective with a first-declension adjective, singular only.

• Nathan J. Ristuccia (2018) Christianization and Commonwealth in Early Medieval Europe: A Ritual Interpretation, Oxford University Press, pages 16–18