The Once and Future King Book 1, Chapter 24
Though there is naturally some resistance to the idea of a young nobody becoming king, most of England's citizens are happy to welcome someone new, because Uther's reign was chaotic. Stronger, more powerful knights were able to bully weaker or poorer people, and there was very little law or justice. All of Arthur's friends, human and animal, send him something in congratulation. Merlyn returns to him then, telling him he will stay for a long time. He tells him that, since he can see the future and the past, he always knew that Arthur was Uther's son-in fact, he was the one who brought Arthur to Sir Ector as an infant in the first place. He knows Arthur's future-- his joys and his sorrows.