Arthurian Passage

In Sanherdrin (21b), Rav teaches that Adoniya, son of David and Chagit, tried to steal the throne, but was unable to, as the throne rejected him. Rashi explains that some of David's descendents had an indentation on their skulls. David's crown had a golden bar from one side to the other, and it would fit only certain offspring of David, thus choosing the next in line.

When learning this, it reminded me of the sword that Arthur pulls out of the stone. There are many more similarities between the legends of Arthur and David the King. Does anyone know of any more?