The late-antique fortifications

Cagliari or Calaris is the main and residential state of the Vice Konigs in Sardinia. From Sardegna DigitalLibrary

Between the middle of the 5th and the middle of the 6th century, Africa and Sardinia were closely and again involved in a common history. In the 5th century, the Vandals, coming from Spain, crossed the Strait of Gibraltar and moved along the coast of Mediterranean Africa. In 439 Genseric conquered Carthage.
Immediately the Vandals “sail for Fluctus Bella Coeperunt”, as Salviano, the priest of Massilia, reports. After the looting of Lilibeo and Palermo in 440 and after the sack of Rome in 455, Genserico organized expeditions to Corsica in 456; one might think that the conquest of Sardinia, a necessary bridgehead, was already under way.
With alternating events, the Vandalic occupation of Africa and Sardinia lasted until 533, when both became Roman again with the Byzantine conquest. Justinian then restored the fortifications, as part of an imperial plan, which involves the strengthening of defensive systems both along the eastern and western “limes”, from Dalmatia to the lower Danube valley, to Liguria, to Spain and especially in North Africa. Here, the largest investments are determined, not only along the internal border, for the defense against Berber incursions, but also in ancient coastal centers, with the restoration of existing walls and with the construction of fortresses “from scratch”.
Nothing therefore prevents the hypothesis that in the 6th century, if not precisely under Justinian, even in Sardinia, a dual defensive system had been built or restored to efficiency, both along the coasts, to defend the strategic points of the road route, and along the internal “limes”, to defend the Barbaricini, along the natural barrier of the Tirso river. Case by case, it will be necessary to decide for fortifying works carried out “from scratch”, possibly under Justinian, and instead survival, at most the readjustment of military structures built before the Vandalic era.
Today, there is a tendency to hypothesize a building 'vacuum' in the vandalism century, rather than a systematic work of dismantling coastal defences by 'barbarians'; nor does it seem that the same centers most exposed to the 'vandalica rabies' of Genserico and Trasamondo have suffered from the change of administration in a specifically traumatic way.
On the other hand, the most recent studies on the origins of Santa Igia, in the early medieval capital of the Giudicato of Cagliari, seem to identify polyeogenetic factors, such as the urban attraction exerted by a martyral sanctuary or by a particularly important cult, different from the poor defensibility of the coast. Nor do they trace its causes to vandalism, which are now largely hypothetical, in a city like Cagliari, probably discontinuous and polycentric, characterized by the presence of structures for diversified use, such as the “castrum” mentioned by Procopio in the passage on the brief Gothic occupation of 552, the same one that the Byzantines, in 530, were able to enter only after showing the head of Zazo, the defeated vandal, to the defenders.

Update

27/11/2025 - 10:26