The Blackface Mountain Sheep is the most common breed of domestic sheep in Ireland. This tough and adaptable breed is often found in the more exposed locations, such as the mountain uplands,along the west coast of Ireland and the Scottish Highlands
Blackfaces are horned in both sexes, and as their name suggests, they usually have a black face (but sometimes with white markings), and black legs. The breed was developed on the Anglo-Scottish border but it is not clear exactly when these sheep became a distinct breed.
Early monastery records show that monks in the 12th century raised sheep that are the progenitors of the modern Scottish Blackface breed. The monks used the wool of the dun-faced sheep, as they were often called, for their own clothing and exported large amounts to Europe.
Latter records show that in 1503 James IV of Scotland established a flock of 5,000 Scottish Blackface Sheep in Ettrick Forest in the area south of Peebles in the Borders.The breed spread from the border areas during the 19th century to the Scottish highlands and islands and also to Ireland. They also crossed to the US. Today the Blackface is the most "important" breed in Ireland and Britan. Roughly thirty percent of all sheep in the UK are Scottish Blackface. Reference: http://www.maamcrossmart.com/historymountainblackface.htm