Dictionary of National Biography, 1885-1900/Sinclair, Henry (d.1400?)
SINCLAIR, Sir HENRY, Earl or Prince of Orkney (d. 1400?), was the eldest son of Sir William Sinclair or Saint-Clair (d. 1330) [q. v.], by Isabel—sometimes called Sperra—daughter of Malise, earl of Strathearn, Caithness, and Orkney. According to Hay, he built the dungeon of Roslin and other walls thereabout, together with parks for fallow and red deer (Sinclairs of Roslin p. 17). In 1379 he and a certain Malise Sperra laid claim to the earldom of Orkney, and the claim was decided in Sinclair's favour by Hakon VI of Norway (‘Diploma of Thomas, Bishop of Orkney and Shetland, addressed to Eric, King of Norway, respecting the Genealogy of William Saint Clair, Earl of Orkney,’ in the Bannatyne Club Miscellany). He held a sort of sovereign power over the islands under the king of Norway, and maintained a royal state.
In 1391 the earl was engaged in the conquest of Frislanda (the Faroe Isles), and fell in with the Venetian voyager, Nicolo Zeno, who happened to be wrecked there and was rescued by the earl (whose name appears in the Voyages of the brothers Zeno as Zichmi). The earl received Zeno into his service as captain of his fleet. After the conquest of the Faroe Islands Nicolo Zeno and his brother Antonio assisted the earl in wresting Shetland from the usurper, Malise Sperra, who was slain during the contest. Nicolo died some time afterwards, but Antonio remained in the earl's service, and undertook to make a voyage to verify the reports of some fishermen regarding the discovery of a rich and populous country in the far west, whither they had been driven by a storm. Sinclair accompanied Antonio on the voyage, and after, in consequence of a fog, drifting south till they touched land at Icara (possibly Kerry in Ireland), they sailed across the Atlantic to a harbour somewhere in Greenland. There Sinclair remained some time after Antonio Zeno's return, ‘exploring the whole of the coast with great diligence.’ He died about 1400. He was married, first, to a daughter of the king of Denmark (Olaus V), by whom he had no issue; and, secondly, to Jean, daughter of Walter Haliburton, lord Dirleton, by whom he had a son Henry (d. 1418) [q. v.], who succeeded him.[Hay's Genealogy of the Sinclairs of Roslin; Torfaeus' Hist. of Orkney; The Voyages of the Venetian brothers Nicolo and Antonio Zeno, in the Hakluyt Soc. 1873; Fiske's Discovery of America; Sinclair's Caithness Events.]