Belisama is a Celtic goddess. She was identified by Roman commentators with Minerva by interpretatio romana.
photograph of the Saint-Lizier inscription
Interpretatio graeca, or "interpretation by means of Greek [models]", refers to the tendency of the ancient Greeks to identify foreign deities with their own gods. It is a discourse used to interpret or attempt to understand the mythology and religion of other cultures; a comparative methodology using ancient Greek religious concepts and practices, deities, and myths, equivalencies, and shared characteristics.
A Roman wall painting showing the Egyptian goddess Isis (seated right) welcoming the Greek heroine Io to Egypt
A Roman fresco from Herculaneum depicting Hercules (from Etruscan Hercle and ultimately Greek Heracles) and Achelous (patron deity of the Achelous River in Greece) from Greco-Roman mythology, 1st century AD
Gilt bronze head from the cult statue of Sulis Minerva from the Temple at Bath
Jupiter Ammon (terracotta of Hellenistic style, 1st century AD)