The Greater Swiss Mountain Dog (German: Grosser Schweizer Sennenhund or French: Grand Bouvier Suisse) is a dog breed which was developed in the Swiss Alps. The name Sennenhund refers to people called Senn or Senner, dairymen and herders in the Swiss Alps. Greater Swiss Mountain Dogs are almost certainly the result of indigenous dogs mating with large mastiff types brought to Switzerland by foreign settlers. At one time, the breed was believed to have been among the most popular in Switzerland. It was assumed to have almost died out by the late 19th century, since its work was being done by other breeds or machines, but was rediscovered in the early 1900s. Greater Swiss Mountain Dogs have an animated and gentle expression. Their eyes are almond shaped, vary in color from hazel to chestnut – dark brown is preferred – medium-sized, and neither deep set nor protruding. Eyelids are close fitting and eyerims are black.