I can’t believe that I forgot to hit the “Publish” button last night on yesterday’s post…
Yesterday I was asking when the word “Christianity” appears in our sources. In Greek it is Χριστιανισμός, and it appears in Ignatius of Antioch; then in Origen; and then in post-Nicene sources. It’s not a widely-used word in surviving ante-Nicene literature, plainly.
But today I wondered what the Latin word might be. I thought perhaps “Christianitas”, with Romanitas in mind. But a little searching around gave me:
Christĭānĭtas , ātis, f. Christus.
I. Christianity, = Christianismus, Cod. Th. 16, 7, 7; 12, 1, 112.—
II. Meton., the Christian clergy, Cod. Th. 12, 1, 123.
So the rather Germanic-sounding Christianismus is our word, originating with Tertullian – who else? – in Adversus Marcionem book 4, chapter 33, verse 8:
 Quasi non et nos limite in quendam agnoscamus Ioannem constitutum inter vetera et nova, ad quem desineret Iudaismus et a quo inciperet Christianismus, non tamen ut ab alia virtute facta sit sedatio legis et prophetarum, et initiatio evangelii in quo est dei regnum, Christus ipse.
As though we too did not know that John has been set as a sort of dividing-line between old things and new, a line at which Judaism should cease and Christianity should begin—not however that by the action of any alien power there came about this cessation of the law and the prophets, and the inception of that gospel in which is the kingdom of God, Christ himself.
I don’t have access as far as I know to any search tool for Latin texts like the TLG, but it does indeed make sense that Tertullian would originate the term, as the first of the Latin fathers. Equally it makes sense that the Latin term should be the Greek term, transliterated.
But the mention of “Judaismus” is interesting. Ignatius also uses “Christianity” as a foil for “Judaism” (Ἰουδαϊσμὸς). Possibly the term “Christianity” exists solely because of the existence of “Judaism”, and the fact that Christians were not included in it?
I wondered how frequently Ἰουδαϊσμὸς or Ἰουδαϊσμὸν, etc was used, so I did a search. Here again it was Ignatius, Origen, then post-Nicene writers! Although in this case it also appears in the fragments of Porphyry’s Against the Christians. This is surprising really.
A google search reveals that it also appears in 2 Maccabees, so perhaps my lack of results is a reflection of the search tool available to me.