There are two strains of this breed, black or white, both originated in the Wensleydale region of North Yorkshire and are known for their lustrous ringlets of wool. The breed was developed in the 19th century by crossing an English Leicester with Teeswater sheep to produce a ram called Blue Cap in 1838. One of the largest and heaviest of all sheep breeds and categorised as ‘at risk’ by the Rare Breeds Survival Trust, at one point it had fewer than 1500 registered breeding females. It is predominantly used today as a ram breed to cross with other breeds to obtain market lambs and for its high-quality wool.