Deultum in Thracia, 217-218 AD., Macrinus, 3 Assaria, Jurukova 61 var.

Deultum in Thracia, Macrinus, 217-218 AD.,
3 Assaria / Æ25 (ø 23-25 mm / 9,36 g), probably brass, axes about medal alignment ↑↑ (ca. 30°),
Obv.: IMP M OPEL SEV - MACRINVS P A , his radiate head right.
Rev.: COL FL PAC – DEV[LT] , Perseus standing left, with right foot on rock, holding head of Medusa and harpa in left hand, freeing Andromeda with right; below, sea-monster serpent Ketos (Cetus) turned to stone.
Jurukova, Deultum p. 68, no. 61 var. (bust type, legends) ; .

This reverse type reflects an established tradition of depicting Perseus and Andromeda. Similar conceptions of the rescue of the princess following the slaying of the Cetus Aethiopicus (“Ethiopian sea-monster”) are found on frescoes and mosaics.
On the way back to Seriphos Island, Perseus stopped in the kingdom of Aethiopia. This mythical Ethiopia was ruled by King Cepheus and Queen Cassiopeia. Cassiopeia, having boasted her daughter Andromeda equal in beauty to the Nereids, drew the vengeance of Poseidon, who sent an inundation on the land and a sea serpent, Cetus, which destroyed man and beast. The oracle of Ammon announced that no relief would be found until the king exposed his daughter Andromeda to the monster, and so she was fastened naked to a rock on the shore. Perseus slew the monster and, setting her free, claimed her in marriage.
More on https://en.wikipedia.org/wiki/Perseus