So starting off with the story of Excaliber. It's the legend of King Arthur and Merlin. Arthur was a king and Merlin was a very powerful wizard who was instrumental in Arthur's success. So basically the two were a dynamic duo. Different expertise but great results when combined.

The sword was encased in stone and when nobody else could Arthur pulled it out like it was butter. Because it was meant to be.

The sword itself has magical properties as well.