"Al Khamsa" is a designation applied to specific desert-bred bloodlines of the Arabian horse considered particularly "pure" by Arabian horse breeders, who sometimes also describe such lines with by use of the Arabic word asil, meaning "pure".
Al Khamsa roughly translates as 'The Five'. It refers to a mythical group of foundation mares that were the legendary founders of the Arabian breed. While some breeders claim these mares really existed, there is no objective, historical way to verify such a claim. The modern definition of an Arabian as Al Khamsa usually refers to a horse that can be verified in every line of its pedigree to trace to specific named desert-bred Arabians with documentation that their breeding was attested to by a Bedouin seller who had sworn a formal oath (generally invoking Allah) that the animal was asil or pure of blood. This standard is only met by approximately two percent of all registered Arabians today. Such horses included the desert-bred imports of the Crabbet Arabian Stud, the imports from Syria of Homer Davenport, many of the horses imported from Egypt that were originally bred by Muhammad Ali of Egypt, Abbas Pasha, Ali Pasha Sherif, or the Royal Agricultural Society and its successor organizations, and other desert-bred horses obtained throughout the Middle East by buyers such as Carl Raswan who were familiar with bloodlines and the formal sales procedures of the Bedouin to properly document animals of Asil bloodlines.
Al Khamsa is a nonprofit organization in the United States that supports the breeding of certain strains of purebred Arabian horses. The name derives from the Al Khamsa ("the five") Arabian mares, the name applied to the legendary five favorite horses of Mohammed. The particular purpose of Al Khamsa is to preserve the original Bedouin Arabian horse in pure bloodlines in the United States.
Some of the pure Arabians in the United States trace their ancestry in whole or part to the Davenport horses collected and preserved by Homer Davenport and others in the late nineteenth century. Others are more recent imports from Egypt. Some of the horses imported from the desert to the Crabbet Arabian Stud by Wilfrid Blunt and Lady Anne Blunt also qualify with this designation.