The "Consularia Constantinopolitana" and the "Chronicon Paschale" both say Constantine and Licinius chose co-emperors on 1 March 317. Constantine and his co-emperor made their three sons their junior co-emperors (their ). Crispus and Constantine II (Constantine's sons) and Licinius II (Licinius's son) were each made "caesar" at Serdica (Sofia, Bulgaria). Constantine was Roman consul for the fifth time in 319. He was consul for the sixth time in 320. On the 25 July 320, it was Constantine's fifteenth anniversary as emperor (his ).