Anet, please quit naming unique items after historical items from the real world. Tyria is supposed to be its own unique world and should have no connection with planet Earth. The new legendary focus titled Ars Goetia is actually a 17th century book about summoning demons. It was later revised by Alister Crowley in the 20th century. Why do you have to connect Tyria with this kind of kitten? I prefer fantasy pretend world.
just google ars goetia and you will see what I am talking about