On February 20, 1472, Scotland annexed the Orkney and Shetland Islands from Norway. The annexation occurred due to Norwegian King Christian I pledging the islands against a dowry for his daughter's marriage to King James III.
Annexation, as passed by Parliament (on the date above), formalized the transfer of power from Earl William Sinclair to Scotland, in exchange for the castle and lands of Ravenscraig in Fife. The Sinclairs had been Earls of Orkney since 1379, when Henry Sinclair, Baron of Roslin gained the title over two rival claimants. Henry has been the subject of much recent attention over a possible voyage taken to the New World nearly a century before Columbus' visit. Earl William built Roslin Chapel.
Walter Scott visited the Orkney Islands and the Shetlands as part of his trip with the Northern Lighthouse Service in 1814, using these islands as setting for "The Pirate". The pirate character is taken from several real accounts of John Gow, who was executed in 1725 (covered by Daniel DeFoe).