The altar, made of Jura limestone, is 1.56 m high, 0.79m wide and 0.75m deep, and was found in 1992 by construction workers in Jakobvorstadt, Gänsbühl, Augsburg, in a former arm of the Lech, almost 400 m outside the former Roman city area. It is possible that it was originally displayed in the immediate area of the find location at a river crossing. The stone probably also had a statue of the goddess Victoria, but this is now lost; the base plate survives, however. As common in this period, it was a recycled monument. The original dedication, dating to the time of Severus Alexander, managed to survive above the actual inscription, hidden under a lipped stone lid, as were working marks on the side corners of the cornice. The older inscription: The later inscription: Lines 10 and 11 with the names of the Rhaetian governor and the ruler of the Gallic Empire were later erased. The name of the usurper Postumus seems to have been made illegible using a chisel, while the remaining letters of these lines were simply scratched out. However, enough survives for the original text to be fully reconstructed.
Historical context
In autumn/winter of 259 the Juthungi, including the Suebi, crossed the Limes Germanicus and invaded Italy. While Emperor Gallienus managed to defeat the German invasion at Mediolanum in 260, the Juthungi had already stopped further north with thousands of Italian captives and copious booty. The inscription of the victory altar indicates that these were met by regular Roman troops and a provincial levy near the Rhaetian provincial capital, and defeated in a two-day battle. Until the discovery of the altar, this event was not known. In addition to the record of this event, the inscription also allows further clarification of the expansion and chronology of the so-called Gallic Empire. Until its discovery, no source indicated that the province of Rhaetia was a part of it; apparently the break-away empire was also established earlier than had previously been assumed. This battle took place in spring, when Emperor Gallienus was still the undisputed and sole ruler of the Empire. But he was not named on the altar since Postumus had already declared himself emperor by the time the inscription was produced in autumn. It was originally assumed that Postumus' usurpation took place only in autumn of 260, but Postumus must have rebelled from his authority already some time before September of this year, probably in June or July. Naturally, after his proclamation a reference to Gallienus was impossible, even though we still don't know when Genialis changed sides. Nevertheless, the political situation changed rapidly. Probably in 262/3, but by 265 at the latest, the Rhaetians were back under the control of Gallienus. At this point followers and supporters of Postumus fell under the damnatio memoriae. The name of Genialis and the consuls as well as the mention of the army were erased from the inscription; probably they were only covered with stucco and remained readable. The composition of the partially Roman army at this battle is typical of the period. This force, led by Genialis, an officer from the equites, lacks any regular units of the Rhaetian provincial army, such as the legio III Italica. Instead the contingent was formed of Germaniciani, milites provinciae Raetiae and populares, which might mean just armed civilians. Perhaps the latter were a kind of citizen militia, raised from the residents of the provincial capital and its hinterland and therefore highly motivated to defeat the German raiders.
