The Muses were a Tirolian female clone Triumvirate that existed within the society of the Robotech Masters. They were responsible for playing set musical instruments that kept the clone population orderly, calm and content. Among the known Muses included Musica and her clone sisters Allegra and Octavia.
After the discovery of the SDF-1, the Muses were stationed onboard the Tirolian Motherships when they abandoned Tirol to recover Zor's Protoculture Matrix on Earth. As such, they were present during the Second Robotech War that was fought against the United Earth Forces. During this time, Musica met and fell in love with the Human Bowie Grant which led to her abandoning her people to be with him. This led to the remaining two Muses being imprisoned in a detention block for the crimes of their sister.
At the climax of the war, only Musica and Allegra survived as they along with the Tirolian civilian population escaped their Mothership before it was destroyed.
The group were only referred to as the Muses after Musica abandoned her people though its not known whether there were other such Triumvirates present onboard the other Motherships or just the Masters flagship.