When we want to know about the origins of the principle of possession as criterium to qualify the standing of defendant in the Roman civil procedure, we inevitably encounter source problems. This article traces a strain of antiquarian informations. Out of the examinations appears that vindiciae or vindicta had been ritual word denoting possession, and the Annalistic traditions around the tale of Verginia had had much to do with the problem. This cluster of traditions seems to have pertinence only to causa liberalis, but this is only for the reason that the vehicle of transmission was this procedure which had been differentiated from a common ritual. This ritual had been incorporated in the corpus of the Twelve Tables and had marked the birth of the civil procedure itself with those. Through the analysis of various versions of etiological myth for this ritual we can know also about what factors contributed to create this principle and this procedure and what it means.