Plato called this female poet the "tenth muse"
Whom 
Plato called "the tenth Muse" (6)  SAPPHO ... Greek female poet (6)  SAPPHO ... 
the Greek lyric poet of Lesbos; much admired although only fragments of her... [DOC] [TLE] Brooklyn Museum: Sappho [PAR] Called the Tenth Muse by Plato, Sappho was a prolific poet of ancient Greece.