Watch List notes:

Constantius II caesar, 324 – 337.
Medallion of 1 ½ solidus, Treviri circa 326-327, AV 6.43 g. FL IVL CONSTANTIVS NOB CAES Laureate, draped and cuirassed bust r. Rev. PRINCIPI IVVENTVTIS Caesar standing r., holding transverse spear and globe. In exergue, T R. C –, cf. 152. RIC 495 (this coin listed). Depeyrot p. 151 (this coin listed).
Of the highest rarity. A very attractive portrait of fine style,
pierced and plugged, otherwise good very fine

Ex Gilhofer/Rauschburg-Hess 22 May 1935, Trau, 4263; Rauch 103, 2017, 526 and Auctiones e-57, 2017, 79 sales.
In AD 317, Constantius II became the second son born to Constantine the Great and Fausta and younger brother to Constantine II. However, while Constantine II had been named Caesar a year after his birth, this title was not bestowed upon Constantine II until after his father had overthrown Licinius I at the Battle of Chrysopolis in AD 324 (i.e., at the age of seven). In AD 332, Constantius II waged a successful war against the Visigoths along the Danube frontier, for which he received the title Germanicus Maximus, and two years later enjoyed further military success against the Sarmatians. He was clearly a skilled commander who enjoyed the support of the eastern armies, and therefore his father placed him in charge of his long-planned war against the Sasanian Persian Empire in AD 337. Unfortunately, Constantine the Great fell ill and died in May of the same year, just as the campaign was beginning. Faced with the death of his father and the prospect of a long conflict in the east, Constantius II immediately formed a pact with his older brother Constantine II and his younger brother Constans to purge all potential rivals from their family and divide the Empire. Constantius II became Augustus in the eastern provinces and retained possession of Constantinople while his brothers were named Augusti over the western provinces. He then turned his attention to the war against the Persians, which was destined to consume much of his reign. However, conflicts between his brothers and western usurpers meant that by AD 350, Constantius II was rid of both Constantine II and Constans. A respite in the Persian war gave Constantius II opportunity to crush the usurpers Magnentius and Vetranio in AD 351-353, thereby unifying the Roman Empire under one man for the first time since the fall of Licinius in AD 324. After an abortive appointment of his cousin Constantius Gallus as Caesar in Gaul, Constantius II settled on Gallus' half-brother Julian as a replacement. After new campaigns against the Sarmatians and the Germanic Quadi along the Danube frontier, Constantius II returned to the simmering conflict with the Persians. Unfortunately, when he requested that Julian send him reinforcements, the Gallic legions mutinied on behalf of Julian as a rival Augustus in the West. When Julian refused to lay down his claims to full imperial power, Constantius II was forced to extricate himself from the Persian war and begin a march on Gaul. He never made it. Instead he fell ill and died in late AD 361 having only reached as far as Mopsuestia in Cilicia. This extremely rare gold solidus multiple advertises Constantius II as princeps iuventutis ("Prince of the Youth") a title indicating his designation as an imperial heir. The term was originally a title for members of the Equestrian order in the Roman Republic, but took on the specific meaning of "crown prince" under Augustus. Thus, the title harks back to the very beginning of the Roman Empire and takes advantage of the air of legitimacy bestowed by its first emperor. The type depicting Constantius II with spear and globe, was also traditional, but seems to go back only to the mid-third century AD, when it was first used on coins of Philip II serving as Caesar to his father Philip I (AD 244-247). The present solidus was probably struck to advertise his status on the occasion of the consulship that Constantius II held alongside his father in AD 328.