The paper focuses on the position of a free person alieni iuris and his/her pater familias in the situation when such person alieni iuris is unlawfully taken away from the power of his/her pater familias, i. e. he/she is an object of the delict. Such merit of facts constituted a private delict and was at first treated as a theft (see Gai 3,199), later on, concurrently, as kidnapping (plagium).
The crimen plagii, which was introduced by the lex Fabia de plagiariis in the 1st century BC and amplified by further imperial legislation, was a special public offence. Regarding private legal instruments available only to the pater familias, we may encounter the actiones (rei vindicatio - legal tool to enforce the ius vindicandi of pater familias; or condictio furtiva and actio furti).
There are many questions that should be analysed when speaking about the furtum of the personae alieni iuris. For example, is it possible to evaluate the "price" of a free person in the case of a theft? In addition, the pater familias may enjoy the advantage of the interdicts (i. e. the twinned interdicts for children and for a wife: interdictum de liberis exhibendis / de uxore exhibenda and interdictum de liberis ducendis / de uxoris ducenda), by praeiudicium or by cognitio praetoria (see D. 6, 1, 1, 2 Ulpianus 16 ad ed.).
As far as public criminal law is concerned, the action regarding plagium can be used either by the pater familias or by any other person. The main part of the paper deals with the relations between the above-mentioned legal instruments available to the pater familias enabling him to cope with the situation when he is deprived of his power over a subordinated person (potestas, manus, mancipio) and reclaims back such kidnapped person.
The development and the use or disuse of each legal tool in the Roman history will be analysed, too.