• Hermes's shoulders sagged. "They'll try, Percy. Oh, we'll all try to keep our promise. And maybe for a while things will get better. But we gods have never been good at keeping oaths. You were born because of a broken promise, eh? Eventually we'll become forgetful. We always do." "You can change." Hermes laughed. "After three thousand years, you think the gods can change their nature?" "Yeah," I said. "I do.

    Rick Riordan (2009). “Percy Jackson and the Last Olympian”, p.256, Penguin UK