Events By place Roman Empire November 11—The Congress of Carnuntum: Attempting to keep peace within the Roman Empire, the leaders of the Tetrarchy declare Maxentius and Licinius to be Augusti, while rival contender Constantine I is declared Caesar of Britain and Gaul. Under Constantine I, the Romans defeat the Germans along the Rhine. Maxentius starts the construction of the basilica bearing his name, the largest building in the Roman Forum. Asia Kingdom of Xiongnu established in northern… (More on 308)