From the first reference to Romulus by Alcimus, a historian from the mid-fourth century BC, where the hero appears alone, down to the age of Augustus, the story of the foundation of Rome underwent considerable plot changes. The two most important are, firstly, Romulus' later role not merely as a conditor urbis, but - in keeping with the Hellenistic tradition of ktiseis poleon - mainly as a creator gentis and a model of the new Roman, who can subsequently embody a new ethnic identity; and, secondly, the later dichotomy of the founders. The interpretation of the Roman foundation myth must be therefore closely associated with the symbolism of numbers - one founder as opposed to twin founders - as it is reflected in different socio-political and historical contexts. In addition to shaping society, myth also documents all its changes. In the context of replacing a single founder with twin founders, Romulus and Remus, the first critical change is the introduction of Remus. The twin founders imply a double community, a notion which becomes meaningful in Rome only after the plebeian achievement of political equality between 367 and 342 BC. The second significant change is the death of Remus, involving the notion of a foundation sacrifice, for which the evidence points to the crisis of 296 BC. The foundation story also serves as an explanation model for the events in the Late Roman Republic. Horace's pessimistic Seventh Epode evokes the foundation crime of fratricide to explain the tragic pattern of civil wars. As Romulus' successors, the Romans are also heirs to his crime, to the scelus fraternae necis, from which they cannot escape. Moreover, Romulus as a creator gentis represents a potential source for the Roman change of identity, which was regarded as coincidental with the foundation act. This recurring theme is elaborated first in Ennius' Annals and later in Vergil's Aeneid and Horace's Third ‘Roman Ode’. The central motif is Ennius’ concilium deorum and its discussion of Romulus' apotheosis, which is opposed by Juno on account of his Trojan identity. Juno, the traditional mythological opponent of the Trojans, demands in exchange for Romulus' apotheosis a break with the old Trojan concept. This break is to be reflected in a new name for the city, which shall be named after its founder, chosen by the auspicium contest. The auspicium thus represents the divine election of the Trojans' legitimate successors, while Romulus' apotheosis symbolically fulfils the idea of a cosmic Roman empire predicted in Juno's Roman Ode speech. The two mythological exempla of Troy and Romulus serve as two opposing models, Troy being the eastern, un-Roman principle, and Romulus the embodiment of the Roman principle. In effect, they present the conflict of two different value systems, which is based on moral criteria and a negative characterisation of the eastern principle. These models are intended to guide the political, ideological and moral assessments of Augustan readers faced with watershed historical events. The contemporary allusions can hardly escape an attentive modern reader. The main characteristic that defines the Roman foundation story as a myth is precisely its sensitivity to social and political changes - a prerequisite for its transmission and continuity, as well as an indicator of its social relevance at different moments in history.