The Strategic Role of Thracian Fortifications in the Balkan Wars of Late Antiquity
The strategic role of Thracian cities changed across Late Antiquity thanks to major political events, which resulted in their increasing vulnerability. These events included, in particular, barbarian crossings of the Lower Danube from 376, and the gradual breakdown of the Middle Danube frontier from the late 4th century AD. The first of these developments led to larger numbers of Gothic soldiers in the Diocese of Thrace and the threat of periodic rebellions by these federate troops. The second culminated in the rise of barbarian powers in Pannonia and the Middle Danube capable of launching devastating attacks on eastern Illyricum and Thrace. Because of these military threats, larger and more numerous fortifications sprang up along the Military Highway and Via Egnatia, northern and southern routes into the Haemus Mountains, and in the province of Europa. As well as a ‘defence-in-depth’ system, this network of fortified cities and bases operated as a platform from which imperial armies could launch offensive campaigns against rebellious or invading barbarians.