Mast-step coins in Roman ships: votive offerings to Isis Pelagia?

Mast-step coins have been discovered in Roman shipwrecks dating from the 2nd century BCE to the 4th century CE, and their placement at the foot of the ship’s mainmast was a deliberate act with significant maritime and religious meaning. This article argues that, in antiquity, mast-step coins were votive offerings to a deity associated with the mast and sails of ancient sailing vessels, and it is proposed that this deity was Isis Pelagia, the inventor of navigation and mistress of the sea. Through a discussion of Isis Pelagia’s iconography and other aspects of Isis’ cult, including her sailing festivals and aretalogy, it is posited that the mast came to symbolize the goddess whose natural place was on the decks of Roman ships, holding their billowing sails and guiding them safely to shore. Allegorically, these coins may thus have been placed at the feet of Isis Pelagia.