Suppose In Arthurian legend, Excalibur is the legendary sword of King Arthur, sometimes also attributed with magical powers or associated with the rightful sovereignty of Britain. Sometimes Excalibur and the Sword in the Stone (the proof of Arthur's lineage) are said to be the same weapon, but in most stories, they are considered separate swords.
Can we infer that "Excalibur is a mythological weapon from Greek mythology"? Yes, no, or maybe?