The societas between Rome and the Ilergetes was based on fides, whatever the precise legal nature of the ties that bound them over time. The detail escapes us for the years 218-217, but the military alliance struck by Scipio and Indibilis in 208 can be considered as a proper foedus, i.e. an agreement based on an exchange of oaths and binding upon the Roman people. This treaty was probably ratified afterwards by the Senate and the people. The defections of 206 and 205 indicate that Indibilis had a different conception of fides: he had committed himself to Scipio in a personal capacity and he considered that the alliance had ended with the defeat of Carthage in Hispania and the departure of Scipio. The deditio in fidem of 205 re-established this societas: in 195, fides was at the heart of the discussions between the Ilergetan ambassadors, who had come to ask for help, and Cato, who sought to respect his duties towards the socii while preserving his troops.