It started with Full Cast Audio's Hercules by Geraldine McCaughrean. Then the 6-book series Mary Pope Osborne's Tales From The Odyssey. Serena is completely drawn into the world of Greek myths and the gods & goddesses of Mount Olympus. She enjoyed so much the story of Odysseus' long journey home from the Trojan War that when she heard of Homer's other classic epic poem, Iliad, she wanted to read it. That is, until I showed her the real thing, which doesn't come translated in any kid-friendly versions as far as I know.
Classic Myths to Read Aloud: The Great Stories of Greek and Roman Mythology by William F. Russell
National Geographic's Treasury of Greek Mythology: Classic Stories of Gods, Goddesses, Heroes & Monsters by Donna Jo Napoli.