The article makes an attempt at interpreting the Latin syntactic-semantic structure traditionally referred to as nominativus cum infinitivo, with the application of the methodological premises of semantic syntax described in the Gramatyka Współczesnego Języka Polskiego (Składnia) [A Grammar of the Modern Polish Language (Syntax)] published in 1984. The structure which is interpreted is a sentence in nature. Its constitutive element is the finite form of the verb in passivum accommodated by the noun-based nominative element (the subject) which constitutes the exponent of an argument of the predicate represented by the verbal form in the infinitive. Traditionally this structure was characterised as a result of the passivisation of structures which are known as accusativus cum infinitivo. However, such an approach is not justifiable neither formally nor semantically. As a matter of fact, the use of passive finite forms within the framework of the nominativus cum infinitivo structures does not determine the sentence diathesis, but it constitutes an index of imparting a marked epistemic modality to the predicative content expressed by the infinitival form. Therefore in terms of semantic syntax the type of a sentence which is discussed should be interpreted as a formalisation of the predicative-argumentative structure featuring a predicate of a higher order, in which the core predicate is of modal nature.