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.

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.

[3] From this evidence it appears that Elmet was one of a number of Sub-Roman Brittonic realms in the Hen Ogledd – what is now northern England and southern Scotland – during the Early Middle Ages.

The historian Alex Woolf suggests that the region of Elmet had a distinct tribal identity in pre-Roman times and that this re-emerged after Roman rule collapsed.

It is generally presumed that Ceretic was the same person known in Welsh sources as Ceredig ap Gwallog, king of Elmet.

A number of ancestors of Ceretic are recorded in Welsh sources: one of Taliesin's poems is for his father, Gwallog ap Lleenog, who may have ruled Elmet near the end of the 6th century.

The Life of Cathróe of Metz mentions Loidam Civitatem as the boundary between the Norsemen of Scandinavian York and the Celtic Britons of the Kingdom of Ystrad Clud (Strathclyde).

[13] Around 1865, a Pillar stone with a 5th or early 6th century inscription was found at St Aelhaearn's Church, Llanaelhaearn in Gwynedd.

It is believed that this refers to an otherwise unattested Aliotus from the Kingdom of Elmet who may have been active in the area before Saint Aelhaiarn founded his church.