and their specialties are traditionally: Calliope (epic poetry), Clio (history), Erato (love poetry, lyric art), Euterpe (music, especially flute), Melpomene (tragedy), Polymnia (hymns), Terpsichore (dance), Thalia (comedy), Urania (astronomy)". "They were considered the source of the knowledge, related orally for centuries in the ancient culture, that was contained in poetic lyrics