Medusa heads were ubiquitous until the end of Greco-Roman antiquity. In amuletic jewelry they were protective amulets1 repelling onlookers2. Such rare amulets mainly in faience2 are of the Roman Period
References
1See the description of MET #10.130.1428
2Petrie W M F, Amulets, 1914, p. 28 and Figs. 128a,b,c


