The priests of Cybele (Cybebe in some places) were eunuchs known as Galli (singular: Gallus). Thus, the meter that Catullus 63, as well as the ritual hymns sung to Cybele, were in, was known as Galliambic.

This meter was remarkable in that the last four or five syllables of each line were supposed to all be short, unstressed syllables. This is particularly difficult in Latin, more suited to Greek. The very rapid cadence of the second half of a line was supposed to mimic the rapid clicking of little cymbals.

Cybele was also known as Magna Mater - in Latin, Great Mother. Being from Asia Minor, she is associated by Catullus with the mountain Dindymus in Phrygia.