system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Was King Arthur a real person in this universe?

Merlin, the wizard mentor in the legends of Arthur, is a central figure in the history of wizardkind, and Morgan Le Fay is also mentioned to exist. So, did King Arthur himself exist as well? Was he a wizard himself, or a muggle?
gpt
Yes. The old but canonical Pottermore site—the one that was sort of like a game where you could collect items and such—had a Chocolate Frog Card for Melin which said:

> Merlin is the most famous wizard of all time. He is sometimes known as the Prince of Enchanters and was part of the Court of King Arthur. 

Note that for this would be true it means the Potterverse and our world must have divergent histories. In our world, the first mention of Arthur in literature shows up in 9th century, but the Potterverse's Merlin was born in the 10th century.