Furthermore , the conflict between Niobe and Leto is mentioned in one of Sappho 's poetic fragments , ( `` Before they were mothers , Leto and Niobe had been the most devoted of friends . '' ) Furthermore , the conflict between Niobe and Leto is mentioned in one of Sappho 's poetic fragments ( `` Before they were mothers , Leto and Niobe had been the most devoted of friends . '' ) .