The present diploma ? on the basis of Cicero?s private-law speech pro Caecina - concentrates on the law of interdicts and the protection of possession in classical roman law. In particular, the two interdicts de vi armata and unde vi are discussed. Based on Cicero?s interpretation of these interdicts the requirements for their applicability are compiled, though especially the circumstances of the present lawsuit have to be considered. The initial points of this diploma are, therefore, the litigant?s opposing positions. Because of the possessory-law character of the interdicts the main attentions are given to questions on possession (eg. its nature and its obtaining). One has to notice that Cicero?s argumentation often seems to differ with the basic principles of roman law of interdicts and possession ? these divergences establish another main focus of this diploma. Moreover, violence (vis) and its practice, which constitute a nesessary requirement for the applicability of both interdicts, are implicit and explicit elements of the case. This is important, because in 69 BC, when the lawsuit took place, the roman society was marked by an amount of violent influences, which explicates the increased use of these legal means. Beside the detailed elaborations of possessio the diploma deals with questions on the right of usufruct and ownership. Finally, a digression concerning rhetorical questions in the speech pro Caecina is carried out; especially the rhetorical status scripti et voluntatis is defined. This raises the question, whether Cicero is in his speech on the side of the strict wording of the interdict (scriptum) or on the side of its purpose (voluntas).