The 7th century King and Saint, Oswald, founded the kingdom of Northumbria by merging his domain of Bernicia with its southern neighbour Deira. The Venerable Bede, England’s first historian, writing in his “Historia Ecclesiastica Gentis Anglorum” describes Oswald’s tomb where “…they hung up over the monument his banner made of gold and purple;” It is probable that this description caused the mediaeval heralds to assign arms of eight alternate stripes of red and gold (yellow) to Bernicia. It is reported that in the Middle Ages the same colours were flown by the first Earl of Northumberland, Henry Percy. Accordingly the county council of Northumberland, a county which formed much of the territory of the dark age kingdom of Northumbria, was awarded arms in 1951 which included a striped pattern of red and yellow bars – this in turn led to the registration of the Northumberland county flag.
In 2015 the Flag Institute additionally registered the originally reported banner of King Oswald, as the flag of the greater region and former kingdom of Northumbria. The shade used in the registered flag is carmine red, a tone between the purple of Bede’s era and the red stripes used by Henry Percy.