Horum iudex erat praefectus fabrum. Vegezio e la praefectura fabrum

The post of praefectus fabrum was granted by a magistrate cum imperio on the basis of trust, loyalty, and competence. In general, the appointees have been described as ‘senior officers on the staff’ of the appointing magistrates. However, little is known about the tasks attached to the post, even if the praefectura fabrum is well attested both in literary texts and inscriptions. The Epitoma rei militaris is the only extant source devoting a passage to the duties of the prefects of engineers. In spite of being a detailed description of the post, this passage has generally been dismissed – notably by H. Maué and B. Dobson – as untrustworthy or useless for a number of reasons, including the fact that, at the time of the Epitoma’s composition, the praefectura fabrum was no more than a relic, or a name in ancient texts and inscriptions. According to Vegetius, the prefect led the corps of technicians attached to the legions. Moreover, he was put in charge of siege machines and the supply of projectiles and other materials. Even if this description and what is known about the praefectura fabrum are not consistent, a re-examination of the passage and of the text as a whole is needed. In fact, the Epitoma reveals a deeper knowledge of the importance attached to the post than expected in such a late source. A focus on this text will offer some useful insights on the sources available to Vegetius, and to what they stated about the tasks attached to the praefectus itself. In addition to this, it will be possible to trace the duties of the post back to its origins and investigate on how the praefectura fabrum became the institutional and political office which we known from the available sources.