Scotland in the Early Middle Ages to be adopted for house building, often combining layers of stone with turf. Place-name evidence, particularly the use of the prefix "pit", meaning land or a field, suggests that the heaviest areas of Pictish settlement were in modern Fife, Perthshire, Angus, Aberdeen and around the Moray Firth, although later Gaelic migration may have erased some Pictish names from the record. Early Gaelic settlement appears to have been in the regions of the western mainland of Scotland between Cowal and Ardnamurchan, and the adjacent islands, later extending up the West coast in the 8th century. There is place name and archaeological
Pentland Firth referring to the sea lanes of the entire west coast of Scotland down to Kintyre. One version of the 9th-century "Historia Brittonum" states that "the Britons originally filled the whole island with their peoples from the English Channel to the Sea of Orcs". On the Caithness (southern) side the Firth extends from Dunnet Head in the west to Duncansby Head in the east, while on the Orkney (northern) side from Tor Ness on Hoy in the west to Old Head on South Ronaldsay in the east. In the middle of the Firth are two significant islands, Stroma and Swona. The