The story of Securitas
The reverse of the coin shows the personification of Securitas, or security, with a fitting legend that identifies her as such. The figure of Securitas is facing left and is holding a branch in her right hand. On the right side we see another part of the legend, which reads REI PVBLICE. The complete legend thus reads SECVRITAS REI PVBLICE, which loosely translates to ‘security of the commonwealth’. The figure of Securitas was often accompanied by epithets like ‘publica’ or ‘Augusta’, indicating the emperor or state as virtuous. On coins she is often depicted leaning on a column, which seems to be missing from this particular coin.
It is interesting to note why Constantine would have associated his mother Helena with this legend on the reverse, as Securitas was often invoked when danger had been averted. What danger would this have been for the context of this coin? The coin was issued in 327 or 328. According to legend, in 327 Helena had returned from her pilgrimage to the Holy Land, bringing with her the parts of the True Cross, and some other relics. The problem with this explanation is the fact that this legend was only composed after the events, and there is no way to verify it with this coin. Maybe the depiction of Securitas can be explained by more historical events. This period was marked by religious unrest and rebellious army units, especially in the East, during which Constantine returned to Constantinople and his mother Helena was sent to the Eastern provinces, stabilizing the dangerous situation by appeasing the public, donating large sums of money to the army, and to others in need.