William Henry Flower, Richard Lydekker, Edwin Dampier Brickwood, William Fream, and Robert Wallace, 1911 Encyclopædia Britannica, Volume 13… (1911)
“ The third horse of the famous trio, the Godolphin Arabian or Barb, brought to England about five-and-twenty years after the Darley Arabian, will be more particularly referred to further on. All the horses now on the turf or at the stud trace their ancestry in the direct male line to one or other of these three—the Byerly Turk, the Darley Arabian, and the Godolphin Arabian or Barb. In the female line their pedigrees can be traced to other sources, but for all practical purposes it suffices to regard one or other of these three animals as the ultima Thule of racing pedigree. ”
