In Roman mythology, Magna Mater deorum Idaea ("great Idaean mother of the gods") was the name for the originally Phrygian goddess Cybele, as well as Rhea.
Her cult moved from Phrygia to Greece from the 6th century to the 4th. In 205 BC, Rome adopted her cult. Fuller details are at the entry for the Roman cult of Cybele.
Theatrical performances honoured the Goddess between April 4 and April 10, and on the birthday of the Temple of the MagnaMater, located on the Palatine Hill, a public sacrifice was offered by a Praetor before the temple [Dionysius of Halicarnassus, Antiquities of Rome, 2.19.4].
"MagnaMater, as we celebrate the Megalesia today and as today it is proper to offer a salad to you, for these reasons and also in order that a better future may fall on me, my house and my family.
"MagnaMater, Mater Deum, uti Ludi Megalesiaci sint aeterni utique populus romanus quirites tuam tarueam tergam aeterne feriant in mysteria tua, te precor oro obsecroque uti semper protegas populo romano quiritibus sicut eis protexisti ab hostibus carthaginis utique semper incolumes serves populum romanum quirites."
In 204 a delegacy was sent from Rome to the city of Pessinus, in Phrigia, considered the capital of the MagnaMater cult.
The Sanctuary of Goddess MagnaMater on the Palatine Hill in Rome.
It was decided to attribute the actual ruins to the Temple of the MagnaMater mostly thanks to the statue of the Goddess found near the edifice, and now in the close Domus Tiberiana, and to an inscription found on the right side of the façade, that says: M(ater) D(eum) M(agna) I(daea).