The Muses were the Greek goddesses of inspiration in literature, science and the arts. They were the daughters of Zeus and Mnemosyne (the personification of memory), and they were also considered water nymphs. Personifications of knowledge and art, some of the arts of the Muses included Music, Science, Geography, Mathematics, Art, and Drama. They were usually invoked at the beginning of various lyrical poems, such as in the Homeric epics; this happened so that the Muses give inspiration or speak through the poet's words.
There were nine Muses according to Hesiod; Calliope (epic poetry), Clio (history), Euterpe (lyric poetry), Thalia (comedy and pastoral poetry), Melpomene (tragedy), Terpsichore (dance), Erato (love poetry), Polyhymnia (sacred poetry), and Urania (astronomy).