Which historical figure is associated with the battlefield defeat of both Arbogast and Eugenius?

The figure associated with the battlefield defeat of both Arbogast and Eugenius is Theodosius I. In 394 AD, Theodosius I faced off against the usurper Eugenius, who was supported by the general Arbogast. Theodosius successfully defeated both at the Battle of the Frigidus, leading to the downfall of Eugenius and the end of Arbogast's influence. Theodosius' victory was significant because it solidified his control over the Roman Empire and ensured the dominance of Christianity within its governance.

His actions during this conflict were pivotal, as they not only removed rival claimants to power but also helped to strengthen the unity of the empire under one ruler, marking a decisive moment in late Roman history. Theodosius’ legacy includes his efforts in promoting Christianity as the state religion and implementing measures against pagan practices, demonstrating the broader societal shifts occurring during his reign.