The embolimon (Greek, literally an "insert") was a musical number performed between the acts of a play. In Roman theatre, the embolium (Latin, plural embolia) in which Galeria specialized was an interlude, probably solo, performed by a dancing girl or mima. The embolium is treated in modern scholarship as a form of ballet-pantomime requiring turns, leaping, versatility of movement, sudden "freezing," and a particular repertoire of hand gestures.
The embolium interlude was part of the mixed musical-comedy genre called mimus. Roman mimus was regularly performed without masks, in contrast to virtually every other form of ancient theatre for which female roles were performed by men. Mimus gave women opportunities to earn a living as professional entertainers, and Galeria's career is evidence of the long-lived acclaim and financial reward they might achieve. Galeria Copiola is one of only four performers of embolia whose names are preserved, the others being Sophê Theorobathylliana, Phoebe Vocontia, and an Oppius who is the only recorded male embolarius.