Ossetic sets itself apart from the other New Iranian languages by having a relatively elaborate system of nine cases. Since most of them are relatively late innovations, and only four cases (Nom., Gen, Abl., and Iness.) can be traced back to Proto-Iranian, many scholars tend to ascribe the development of the case system to Caucasian influence. The exact nature of this influence, however, has never been demonstrated. The aim of this paper is, first, to not only reconstruct the etymologies of Ossetic cases, but also to provide a chronology of how the case system developed. The second aim pursued here is to give a systematic comparison of the case system of Ossetic with those of the neighbouring languages and to determine if there is any external influence on the case system and, if so, what languages this influence came from. I conclude that Ossetic developed from a case system identical to those of Khotanese and Sogdian towards the present state under the influence of contact with Georgian and, later, with Turkic and Vaynakh languages. In the process of the discussion, I also argue that two new cases, the Directive and Regressive, are undergoing grammaticalisation in contemporary Ossetic.