According to legend, Arthur's Stone marks the spot of one of King Arthur's battles. The King, allegedly, kneeled there and prayed. Hence its name.
However this is only a legend. It was built long before Arthur, somewhere between 3700 and 2700 BC in Neolithic period. It was created before the discovery of metal.
It was raised with primitive tools, proving its significant importance to the builders.
There was a Neolithic settlement discovered on Dorstone Hill.
Most likely Arthur's Stone was a chambered tomb, used to bury the dead for several generations.
It was an object of veneration and worship for many a generation of ancient people. It might contain meaning unknown to modern men.
Originally, Arthurís stone was covered with a mound. Unfortunately, somewhere in the XIX century some of the stones were removed.