system
Given the following post, respond as if you're commenting on Reddit:
human
[Arthurian Legend] Which sword is Excalibur? The sword in the stone? Or the sword from the Lady in the lake? Are they somehow the same sword?
gpt
There are about as many versions of the legend as there are seats at the round table, so there isn’t a true canon. 

That being said, some modern versions that try to square the Lady of the Lake version with the Sword in the Stone version will have them be two separate swords. In these versions the sword in the stone is “Caliburnus/Caliburn” (actually just an archaic name for Excalibur) which he pulled to prove his worth as king, and he later received Excalibur from the Lady.