The Orkneyinga Saga is the primary historical authority for the earldom of Orkney and Northern Scotland spanning three and a half centuries. The narrative commences with the conquest of the islands by Harald Fairhaired and the establishment of the Norse earldom under Rögnvald and his brother Sigurd.
From these beginnings, the saga details the turbulent succession of Norse Jarls who ruled Shetland, Orkney, Caithness, and parts of the Scottish mainland. It records their maritime expeditions, power struggles with Scottish kings, and internal blood feuds that constantly reshaped the political landscape of the region.
A central storyline follows the life and martyrdom of Saint Magnus, whose murder by his cousin Hákon forms the moral and religious turning point of the work. The construction of St. Magnus Cathedral in Kirkwall by Earl Rögnvald Kolson serves as the architectural and spiritual monument to this legacy.
The text blends contemporary skaldic songs with prose chronicles to portray the personal characters, deeds, and violent realities of the northern chiefs. It documents the transition from pagan Norse customs to Christianity, the shifting allegiances between Norwegian and Scottish crowns, and the eventual passing of the old earldom.
The later chapters trace the subsequent lines of the earldom through the houses of Angus and Stratherne down to the St. Clair family. The narrative concludes as the islands are formally pledged to the Scottish crown through royal marriage alliances, drawing the era of independent Norse rule to a close.