Elmet (Elfed), sometimes Elmed or Elmete, was an independent Brittonic Celtic Cumbric speaking kingdom between about the 4th century and mid 7th century. The people of Elmet survived as a distinctly recognized Brittonic Celtic group for centuries afterwards in what later became the smaller area of the West Riding of Yorkshire then West Yorkshire, South Yorkshire and North Derbyshire. The precise borders of the original kingdom of Elmet are unclear. Some have argued that, until the 7th century, it was bounded by the rivers Sheaf in the south and Wharfe in the east. It adjoined the kingdom of Deira to the north and Mercia to the south, and its western boundary appears to have been near Craven, which was possibly also a minor British kingdom. As such, it was not conterminous with other territories of the Britons at the time, being well to the south of others in the Hen Ogledd ("Old North"), such as Strathclyde, and north-east of Wales, Cornwall and Dumnonia. As one of the south-easternmost Brittonic regions for which there is reasonably substantial evidence, Elmet is notable for having survived relatively late in the period of Anglo-Saxon settlement of Britain. The term is used as an affix to place names between Leeds and Selby, including Barwick in Elmet and Sherburn in Elmet. It was thus used more widely in medieval times, for places in the wapentakes of Barkston Ash and Skyrack, including Burton Salmon, Sutton (east of Castleford), Micklefield, Kirkby Wharfe, Saxton, and Clifford. In the tribal hidage, the extent of Elmet is described as 600 hides; while a hide was a unit of value rather than area, 600 hides would probably have encompassed an area slightly larger than the combined total of the wapentakes of Barkston Ash and Skyrack. Hence scholars such as A. H. Smith concluded that those two wapentakes probably approximated much of the area of the former Elmet.