The largest building in the Roman Forum is a basilica named for these two rulers.
While commanding the army of one of these rulers, Ruricius Pompeianus was killed fighting the army of the other. The elder of them married the other's sister and later killed her by having her suffocated in an overheated bath. In a conflict, one of these rulers crossed the Cottian Alps and attacked Segusium when moving against the other. During the war between these two rulers, one offered his sister to Licinius to form an alliance before embarking on a campaign that captured Verona. The largest building in the Roman Forum is a basilica named for these two rulers. After one of them drowned in a chaotic retreat across the Tiber River, the other sent his head to Carthage as proof that he had died. Before one of these men defeated the other, he saw a vision with the words "in hoc signo vinces" appearing next to a cross of light. For 10 points, name these rival emperors of the tetrarchy who squared off at the Battle of the Milvian Bridge.
While commanding the army of one of these rulers, Ruricius Pompeianus was killed fighting the army of the other.
Constantine the Great [or Constantine I; accept Saint Constantine; prompt on "Constantine"] and Maxentius [or Marcus Aurelius Valerius Maxentius Augustus]