This particular coin depicts the profile of Constantine II, deciphered from the legend on the obverse and reverse. He was the second son of the infamous Emperor, Constantine the Great. He was given the title of Caesar by his father in AD 317, 20 years prior to his death. When Constantine I died, his great Empire was divided between his sons; Constantine II, Constantius and Constans. Constantine II originally ruled the provinces of Britain, Gaul and Spain. He died fighting his brother Constans for full control of the Empire.
This particular coin was minted in Siscia, which can be ascertained from the mintmark on the reverse. Beneath the laurel wreath are the letters ΕSIS. The epsilon, E, refers to the officina number, or number of workshops operating at the mint. As epsilon is the fifth letter in the Greek alphabet, it is the 5th officina. SIS is a shortening of Siscia, referring to the mint.