The Raven Banner is booklet written and published by Ian Cassells, Thurso, and illustrated by Jennifer Law, Thurso, circa 1995. It offers a history of Caithness as a part of the Norwegian earldom of Orkney from circa 885 to 1266, and a guide to Viking Caithness. The booklet's title is a reference to the banner of Sigurd Hlodvirsson, Earl of Orkney (Sigurd the Stout), who died at Clontarf in 1014 in a bid to become High King of Ireland.
According to Ian Cassells, Harald Finehair became the first King of all Norway in 885 and it was this king who created the Norwegian earldom of Orkney. In 1266 Caithness was defined as Scottish rather than Norwegian by the Treaty of Perth.
The Raven Banner details Norse associations with twenty locations in Caithness, gives meaning to many of the place names which are Norse in origin, and identifies clan names which appear also to be Norse in origin.