This paper examines the history of the Accusativus cum Infinitivo (henceforth: AcI) construction in some languages of Western Europe (the Romance and Germanic languages), and attempts to ascertain whether the AcI in the modern languages is modelled on the AcI of Latin or whether the form was simply inherited. In this paper, only those constructions which are formed with verbs of saying or thinking + infinitive are considered instances of true AcI constructions. Following Pountain (1998), this paper attempts to distinguish ‘hard’ vs ‘weak’, ‘total’ vs ‘partial’, ‘learnèd’ vs ‘non-learnèd’ Latinisms. In conclusion, it is hypothesized that the construction is favoured by Latin models, but it is consistent with structural patterns already occurring in the languages involved.