This coin bears the head of Emperor Antoninus Pius (AD 86–161) and an image of the Roman God Mars. The presence of a powerful deity on a coin lent authority to the emperor. Mars stands before Rhea Sylvia, the woman with whom he fathered Romulus and Remus, the mythical founders of Rome.
Emperor Antoninus Pius' fulltitle was Caesar Titus Aelius Hadrianus Antoninus Augustus Pius. He was Roman emperor from 138-161AD. Of Gallic origins, he served as consul (120) before being assigned judicial administrative duties in Italy. He later governed the province of Asia (c. 134). He became an adviser to Hadrian and in 138 was made Hadrian's heir. On accession he had the deceased emperor declared a god; for such dutiful acts he was named Pius ("Pious"). Mild-mannered and capable, he was the fourth of the "five good emperors" who guided the empire through an 84-year period (96-180) of internal peace and prosperity.
The aureus was an ancient Roman gold coin, issued from around the 1st century BC up to the 4th century AD. One aureus was worth 25 silver denarii. The denarius was a small silver coin and the principal silver coin issued in the ancient Roman currency system from the late 3rd century BC until the early 3rd century AD.