 Complete the following phrase:  The next year, in 316, Constantine sent his half-brother Julius Constantius, to Licinius at Sirmium, with the proposal of elevating Bassianus to the rank of caesar and with power over Italy. Licinius refused to acknowledge the appointment; furthermore, he told Senecio to contact his brother and have him kill Constantine, take arms and conquer Italy for Licinius. The conspiracy was discovered and Bassianus arrested and put to death. Constantine asked Licinius to hand him Senecio, but Licinius refused and overthrew his colleagues statues at Emona, on the border between the two spheres of influence; these events led to the outbreak of hostilities between Constantine and Licinius, an episode of civil war known as the 