system
Given the following post, respond as if you're commenting on Reddit:
human
[Arthurian Legend] Where did the Sword in the Stone come from?

I feel like this is a dumb question, but I'm having trouble finding the answer. Where did the Sword in the Stone come from? Who stuck it in the stone? Who created the magic which prevented anyone but King Arthur from pulling it?
gpt
In the original telling of the story, the sword and stone (and an anvil) appeared in a church yard on Christmas eve, as did the prophecy foretelling that only a true king could remove it. It was a miracle, put on earth by God for Arthur to find. 

Other tellings say that Merlin orchestrated the sword and stone, as a way of legitimizing Arthur's rule.