For more by Robert Graves, please see: Claudius the God and His Wife Messalina, Goodbye to All That, The Greek Myths: Volumes 1 & 2, The White Goddess: A Historical Grammar of Poetic Myth, and Count Belisarius.
For other works about Ancient Rome, please see: The First Man in Rome by Colleen McCullough, The Twelve Caesars by Suetonius, Imperium: A Novel of Ancient Rome by Robert Harris, The Aeneid by Virgil, or Germania by Tacitus.
For more historical fiction, consider: Memoirs of a Geisha by Arthur Golden, Gone With the Wind by Margaret Mitchell, The Pillars of the Earth by Ken Follett, The Book Thief by Markus Zusak, and The Other Boleyn Girl by Philippa Gregory.
For more historical...