This study identifies and analyses the legal rules followed in Vindolanda, a Roman military settlement erected in the first century AD to separate the Roman province of Britannia from the unconqueredCaledonia. In particular, the focus is on the rules followed by military officers of different ranks stationed therein and the legal powers held by them. This subject has scarcely been explored by Roman law scholars due both to the paucity of Roman legal sources on this point and the traditional conception of Roman military law as of secondary relevance in comparison with Roman private law (although, recently, this opinion has been changing).