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. 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. A third possibility is that a large dog breed was indigenous to central Europe during the Neolithic Period, when humans grew wild and domestic crops and used domesticated animals. Whether or not a domesticated large breed existed in the Alpine area when the Romans invaded, Greater Swiss Mountain Dogs are almost certainly the result of the mating of native farm dogs with large Mastiff-type dogs brought to Switzerland by foreign settlers. The early ancestors of the Greater Swiss Mountain Dog were used by farmers, herdsmen and merchants in central Europe. 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.