three lines used in the English official registers to show the ramifications of a genealogical tree. Sometimes the word purebred is used synonymously with pedigreed, but purebred refers to the animal having a known ancestry, and pedigree refers to the written record of breeding. Not all purebred animals have their lineage in written form. For example, until the 20th century, the Bedouin people of the Arabian peninsula only recorded the ancestry of their Arabian horses via an oral tradition, supported by the swearing of religiously based oaths as to the asil or "pure" breeding of the animal. Conversely, some animals may have a recorded pedigree or even a registry, but not be considered "purebred". Today the modern Anglo-Arabian horse, a cross of Thoroughbred and Arabian bloodlines, is considered such a case. Purebreds by animal Purebred dogs A purebred dog is a dog of a modern breed of dog, with written documentation showing the individual purebred dog's descent from its breeds' foundation stock. In dogs, the term breed is used two ways: loosely, to refer to dog types or landraces of dog (also called natural breeds or ancient breeds); or more precisely, to refer to modern breeds of dog, which are documented so as to be known to be descended from specific ancestors, that closely resemble others of their breed in appearance, movement, way of working and other characters; and that reproduce with offspring closely resembling each other and their parents. Purebred dogs are breeds in the second sense. New breeds of dog are constantly being created, and there are many websites for new breed associations and breed clubs offering legitimate registrations for new or rare breeds. When dogs of a new breed are "visibly similar in most characteristics" and have reliable documented descent from a "known and designated foundation stock", then they can then be considered members of a breed, and, if an individual dog is documented and registered, it can be called purebred. Purebred horses The domestication of the horse resulted in a small number of domesticated stallions (possibly a single male ancestor) being crossed on wild mares that had adapted to local conditions. This ultimately produced horses of four basic body types, once thought to be wild prototypes, but now considered to be landraces. Many of these animals were then bred true to original type by selected breeding, though emphasizing certain inherent traits (such as a good temperament,