Gratian's Campaign against the Lentienses and his Journey to Thrace (Ammianus Marcellinus 31.10 & 31.11.6):A New Chronology

This paper offers a new chronology for Gratian's journey from Trier to Thrace, his campaign against the Lentienses as well as the route he followed in 378, as described by Ammianus Marcellinus (31.10 and 31.11.6). According to Otto Seeck and others, Gratian left Trier shortly after 20 April 378 (Cod. Theod. 8.5.35). It is argued here that Gratian left Trier soon after 1 June (Cod. Theod. 1.15.9), a date dismissed by Seeck on weak grounds, and that the events described by Ammianus perfectly fit within a chronological window of the months June and July of 378.