"How far did auspices hold? An augury was regarded as applying only inside the City, that is, within the pomerium, and only when taken by a magistrate at one of the two auguricula. Auspices were everything else, public or private, taken according to Roman custom. These applied only so far as the next river. That explains why the Roman army had a habit of stopping after entering enemy territory, building a camp just on the other side of a river, as the center of the camp would have an auguriculum and auspices would be taken before proceeding further."


That is a facinating theory! I haden't thought of that before, the Romans building a camp for religious purposes. I wouldn't be suprised if that played a role in it, but I certainly do not believe that is the sole purpose for going through the pains of building a camp at the end of every march. It was tactical consideration and city-state thinking just as much as religion. Well perhaps more so, in my opinion.