Caesar
On the 1 March 317 Licinius II was raised to the imperial rank of caesar by agreement between his father and Constantine. Constantine's sons Crispus and the infant Constantine II were elevated to caesar on the same day, at Serdica (Sofia). The date was chosen especially; it was the dies imperii (date of accession) of Constantine's father and Licinius's father-in-law Constantius I, the grandfather of all the new caesares. Crispus was no older than 17, while Constantine II was, at seven months, even younger than Licinius II, who was then only 20 months old. Sharing the same day of investiture, none of the caesares could claim seniority. Licinius II retained his title until 324, throughout the time his father remained in power.
Licinius is said by Themistius to have been educated by the grammaticus, and later consul, Flavius Optatus. Licinius was mentioned in the inscription of a Roman milestone from Viennensis as Constantini Aug. sororis filius, 'the son of the sister of Constantine Augustus'.
Licinius II was made consul in 319. His colleague was his uncle Constantine. In 321, the relationship between the two augusti had worsened and each made different nominations for the consulship: Licinius II was made consul for the second time with his father in the east, but Constantine and Crispus held the office in the west (see: list of Roman consuls). Licinius's quinquennalia was celebrated on the 1 March 321. The Munich Treasure was made for the occasion of the quinqennalia; besides a silver bust of Licinius I, three large silver bowls were made for largitio, each weighing a Roman pound – 300 grams (11 oz). The largitio bowls were decorated with portraits of the two emperors, with inscriptions celebrating the quinquennalia of Licinius II as well as a vota (vow of good rulership) for a decennalia.
After his defeats by Constantine and Crispus at the Battle of the Hellespont and the Battle of Chrysopolis (18 September 324), Licinius I surrendered himself and his remaining forces to Constantine at Nicomedia. At the intercession of Flavia Julia Constantia, Constantine spared his brother-in-law and nephew. Licinius the Elder retired to Thessalonica as a private citizen. Immediately after his father's defeat and capitulation the Licinius II was stripped of the title of caesar. Constantine seems to have regretted his leniency and the former augustus was hanged in the spring of 325. The former augustus had been accused of plotting to renew hostilities and was executed on this pretext, real or imagined. Licinius's co-emperor and augustus Martinian was also executed, either at this time or in 324. Licinius II survived until the following year.
