The ancient belief, that like is cured by like, has appeared in myth and legend as well as medicine throughout the centuries. Anthropologists have described its functions in relatively undeveloped societies, and a prominent example in legend is in Wagner’s Tristan and Isolde only a touch of the spear that wounded Tristan can heal him. Similia similibus curentur is the conceptual basis for homeopathy, which is often defined as the art of curing by administering minute amounts of remedies that produce effects in a healthy person similar to the patient’s symptoms. Historians of homeopathy point out that Hippocrates practiced ancient homeopathy, that it was written about in 4th Century B.D Greece, and that there are references to it in Medieval medical texts.