ABSTRACT. The paper focuses on the invention of a Proto-Latin language for the film Il primo Re by M. Rovere (2019). The language was created with the explicit aim of producing a barbaric and primitivistic effect on the hearer. The method used to invent it is summed up in the formula: back in time, but still in place. We started from Classical Latin and “antiquated” it exploiting the data from historical Latin and Indo-European linguistics, but we avoided mixing Latin with different languages. The result is a particular type of language ex inventione: the single chunks that compose it are all plausible reconstructions from the scientific point of view, but they are not attested and have never co-existed as such. Language science and the human instinct for creativity (verbigeratio ludica) are therefore the two sources from which the language of the film was created.