In Edward, 2nd Duke of York's work "The Master of Game", which was mostly a 15th-century translation of an earlier work by Gaston III of Foix-Béarn entitled "Livre de chasse", Spaniels are described as being from Spain as much as all Greyhounds are from England or Scotland. Sixteenth-century English physician John Caius wrote that the spaniels of the time were mostly white, marked with spots that are commonly red. He described a new variety to have come out of France, which were speckled all over with white and black, "which mingled colours incline to a marble blewe". In the added appendices added to the 1909 re-print of Caius' work, the editors suggested that the type of dogs may have been brought into the British Isles as early as 900 BC by a branch of the Celts moving from Spain into Cornwall and on into Wales, England and Ireland. Theories on the origin of the Welsh Springer Spaniel support this theory, as it is believed that the breed specifically is a direct descendant of the "Agassian hunting dog" described in the hunting poem "Cynegetica" attributed to Oppian of Apamea, which belonged to the Celtic tribes of Roman Britain:  There is a strong breed of hunting dog, small in size but no less worthy of great praise. These the wild tribes of Britons with their tattooed backs rear and call by the name of Agassian. Their size is like that of worthless and greedy domestic table dogs; squat, emaciated, shaggy, dull of eye, but endowed with feet armed with powerful claws and a mouth sharp with close-set venomous tearing teeth. It is by virtue of its nose, however, that the Agassian is most exalted, and for tracking it is the best there is; for it is very adept at discovering the tracks of things that walk upon the ground, and skilled too at marking the airborne scent. Another theory of the origin of the spaniel is that the ancient Romans imported the Spaniel into Britannia, by way of the trade routes to the Far East. Colonel David Hancock adds a belief that the sporting type of spaniel originated in China from the short-faced ancestors of dogs such as the Pekinese, Pug and Shih Tzu. The theory goes that these ancestors were introduced into Southern Europe and evolved into the small sporting spaniels of the period around 1300–1600 AD. The issue of how a short-muzzled dog could evolve into a longer-muzzled dog is addressed by pointing to the evolution of the King Charles Spaniel into the Cavalier King Charles Spaniel in less than a century.