The opposition ptw'si" ojrqhv (eujqei'a) / ptwvsei" plavgiai, which with time began to express the contrast between the nominative and the oblique cases (casus rectus – casus obliqui) in the grammatical tradition, first appeared in the Greek reflection on language most probably in the circle of the Stoic doctrine, where it was used to determine the meanings of nouns perceived from the point of view of their constituting elements of the predicative-argumentative structures which formed propositions (ajxiwvmata). What justifies this statement is the fact that in the framework of the Stoic dialectics concepts denoted by terms ojrqhv ptw'si" and plavgiai ptwvsei" were unambiguously situated in the sphere of the linguistically expressed content (ta; shmainovmena, ta; lektav) and used consistently in connection with the concept of kathgovrhma (‘predicate’), that is the predicative content expressed by the verb. The analysis of the preserved records demonstrates that the term ojrqh; ptw'si" had a meaning of the subjective predicate argument (disregarding the value of the case of the noun which denoted it), whereas ptwvsei" plavgiai had the meaning of the non-subjective arguments implied by multi-argument predicates. Therefore, in the Stoic dialectics the opposition ojrqh; ptw'si" / plavgiai ptwvsei" reflected the hierarchical differentiation of the status of the content expressed by the nouns perceived as arguments of the predicate within the proposition. These terms gained the meaning of the nominative and the oblique cases, respectively, only in the circle of Hellenistic philologists, whose research and analyses were to a greater extent focused on the formal side of linguistic signs (words). Those scholars used the terminological apparatus of the Stoic school, while introducing there some vital modifications, however. With reference to the issue which interests us here, the modification consisted in the identification
of the Stoic ojrqh; ptw'si" with its most frequent language exponent, i.e. the noun in the nominative, and following the same principle, of the Stoic plavgiai ptwvsei" with nouns in the oblique cases. The Hellenistic philological school should probably also be ascribed the introduction of the term eujqei'a ptw'si" as a name of the nominative synonymous with ojrqh; ptw'si", as there are no sufficient premises on which to attribute the use of the adjective eujquv" as an index of that case already to Aristotle.

The opposition ptw'si" ojrqhv (eujqei'a) / ptwvsei" plavgiai, which with time began to express the contrast between the nominative and the oblique cases (casus rectus – casus obliqui) in the grammatical tradition, first appeared in the Greek reflection on language most probably in the circle of the Stoic doctrine, where it was used to determine the meanings of nouns perceived from the point of view of their constituting elements of the predicative-argumentative structures which formed propositions (ajxiwvmata). What justifies this statement is the fact that in the framework of the Stoic dialectics concepts denoted by terms ojrqhv ptw'si" and plavgiai ptwvsei" were unambiguously situated in the sphere of the linguistically expressed content (ta; shmainovmena, ta; lektav) and used consistently in connection with the concept of kathgovrhma (‘predicate’), that is the predicative content expressed by the verb. The analysis of the preserved records demonstrates that the term ojrqh; ptw'si" had a meaning of the subjective predicate argument (disregarding the value of the case of the noun which denoted it), whereas ptwvsei" plavgiai had the meaning of the non-subjective arguments implied by multi-argument predicates. Therefore, in the Stoic dialectics the opposition ojrqh; ptw'si" / plavgiai ptwvsei" reflected the hierarchical differentiation of the status of the content expressed by the nouns perceived as arguments of the predicate within the proposition. These terms gained the meaning of the nominative and the oblique cases, respectively, only in the circle of Hellenistic philologists, whose research and analyses were to a greater extent focused on the formal side of linguistic signs (words). Those scholars used the terminological apparatus of the Stoic school, while introducing there some vital modifications, however. With reference to the issue which interests us here, the modification consisted in the identification
of the Stoic ojrqh; ptw'si" with its most frequent language exponent, i.e. the noun in the nominative, and following the same principle, of the Stoic plavgiai ptwvsei" with nouns in the oblique cases. The Hellenistic philological school should probably also be ascribed the introduction of the term eujqei'a ptw'si" as a name of the nominative synonymous with ojrqh; ptw'si", as there are no sufficient premises on which to attribute the use of the adjective eujquv" as an index of that case already to Aristotle.