Holy Grail

The Holy Grail is not part of the original King Arthur story. It has been included in the Middle Ages by Chr├ętien de Troyes. The reason why he chose to do so, is that it added Christianity to the story. In those these the church had a lot of power. By making King Arthur a noble knight and adding the Christianity, the story was more accepted. It was also a selling trick; legends with elements of Christianity sold really well1.