The Once and Future King Book 3, Chapter 24
The knights from Camelot try to convince Lancelot to return there, but he protests that he owes something to Elaine. They tell him that Guenever is crazy with grief over him, and he tells them, doubtfully, that he loves Elaine. But Elaine feels he is going, and asks him to promise that he will one day return. He promises. Then Uncle Dap arrives, carrying his armor and embroidery done by Guenever. Lancelot leaves for Camelot immediately.