Artemus was one of the Argonauts who sailed with Jason to bring the Golden Fleece to Argos. Ten years later, he was part of the second expedition of the Argo when Castor and the Blood-Eye Cult stole the Golden Fleece. He was initially not in favour of following Jason again because he had been in love with Glauce and blamed Jason for Medea having killed Glauce. Later, he forgave the hero.