The focus of the study is the historical evaluation of a legal text comprising 14 provisions from the reign of Anastasius I (491-518 AD). This law, known in research under the title de rebus Libycis or de rebus Libyae Pentapolis denuo constituendis, was immortalized on stone and discovered in several cities in Cyrenaica, the eastern part of modern Libya. This region was located on the southwestern edge of the (Eastern) Roman Empire and was therefore viewed as a border area. One of the most important innovations of the late Roman period was the organization of such a border area in a ducat, which was placed under the authority of an official known as dux limitis. In this context, Anastasius' provisions offer an excellent insight into an act of political communication between the imperial headquarters, its subordinate administrative bodies and the periphery of the area of rule in the form of the ducal administrative district. The aim of this study is to use a systematic analysis of the law to examine the organizational structures of the Libyan ducat, which were shaped by military requirements. The inscription preserved in Cyrenaica is an imperial constitution and thus a Roman state document. In recent decades, epigraphic research has adopted a fruitful approach of examining such documents and texts in isolation from their location, the public they are directly addressed to, the material used by the inscription bearer and, in individual cases, even the monument that adorned the respective inscription. Anastasius' Libyan military decree was previously dated to 501 AD. However, this was based on an incorrect reading of the imperial title. As part of the investigation, the year 492 AD was determined as the new terminus post quem. Due to this new dating, it was possible to link the emperor's regulations in the Pentapolis with the demand of the capital's population for greater attention to the military interests of the empire, as recorded in the protocol of his accession to the throne. Anastasius complied with this demand in his comprehensive reform of the military. As the Libyan inscriptions now show in detail, this reform can be divided into two parts: In the first part, primarily empire-wide standards were established, reinforced and fine-tuned. In the second part, however, the special regulations for the respective area of application were laid down. It is these regulations that constituted the reform of the ducats. Building on the observations made in Cyrenaica, the other border areas of the Eastern Roman Empire were then examined. It became clear that another important component of the reforms was the expansion of the military infrastructure.