  strathclyde (lit. "strath of the river clyde"), originally  or alclud, was one of the early medieval kingdoms of the celtic people called the britons in the hen ogledd, the brittonic-speaking parts of what is now southern scotland and northern england. the kingdom developed during the post-roman period. it is also known as alt clut, a brittonic term for dumbarton castle, the medieval capital of the region. it may have had its origins with the damnonii people of ptolemy's geography. the language of strathclyde, and that of the britons in surrounding areas under non-native rulership, is known as cumbric, a dialect or language closely related to old welsh. scottish toponymy and archaeology points to some settlement by vikings or norseâgaels (see scandinavian scotland), although to a lesser degree than in neighbouring galloway. a small number of anglian place-names show some limited settlement by incomers from northumbria prior to the norse settlement. due to the series of language changes in the area, it is not possible to say whether any goidelic settlement took place before gaelic was introduced in the high middle ages. after the sack of dumbarton rock by a viking army from dublin in 870, the name strathclyde comes into use, perhaps reflecting 
Former_countries_in_the_British_Isles Former_monarchies_of_Europe Late_Iron_Age_Scotland Scotland_in_the_Early_Middle_Ages