What instrument did Hermes invent in Greek mythology?

In Greek mythology, Hermes invented the lyre.

The Homeric Hymn to Hermes says that the infant god made the instrument from a tortoise shell, stretched animal hide across it, and attached strings. The story presents this invention as evidence of Hermes’s extraordinary cleverness: he creates music soon after birth and uses the lyre in his dealings with Apollo.

Hermes had stolen Apollo’s cattle, and the theft led to a confrontation between the brothers. When Apollo heard the new instrument, he admired its sound. Hermes gave Apollo the lyre, and Apollo in turn accepted Hermes among the gods and received the cattle back.

The lyre later became especially associated with Apollo, even though the myth credits Hermes with inventing it. This is why Apollo is often shown holding a lyre in Greek art, while Hermes’s role is remembered in the instrument’s origin story.