William Sinclair, 1st Earl of Caithness

William Sinclair (1410–1480), 1st Earl of Caithness (1455–1476), last Earl (Jarl) of Orkney (1434–1470 de facto, –1472 de jure), 2nd Lord Sinclair and 11th Baron of Roslin was a Norwegian and Scottish nobleman and the builder of Rosslyn Chapel, in Midlothian.

In The Scots Peerage by James Balfour Paul he is designated as the 1st Lord Sinclair, but historian Roland Saint-Clair designates him the 2nd Lord Sinclair in reference to his father, Henry II Sinclair, Earl of Orkney, being the first person recorded as Lord Sinclair by public records.

Early life

He was the son of Henry II Sinclair, Earl of Orkney and Egidia Douglas, daughter of Sir William Douglas of Nithsdale and maternal granddaughter of Robert II of Scotland. He was also the grandson of Henry I Sinclair, Earl of Orkney.

His father Henry, who had been a de facto Jarl of Orkney, died in 1420; William travelled to Copenhagen in 1422 to establish his claim to the Jarldom, but David Menzies was appointed instead, to rule as William's guardian until he came of age. In 1424, William succeeded in wresting de facto control of the earldom from his guardian, but it was not until 1434 that he was acknowledged as Jarl of Orkney by King Eric VII of Denmark, Norway and Sweden, sovereign of Orkney.

Earl of Orkney

On succeeding to the Earldom of Orkney, William had barely been in possession of it for a year when he was one of five earls selected to be among twenty hostages, proposed on 31 May 1421, for the redemption of James I of Scotland. When that redemption could not be obtained, he was then placed on the list of nobles who received a passport to visit James I, who was then a prisoner in England. The earl received a safe conduct for himself and twenty-four persons. James I returned to Scotland in 1424 and he was met at Durham by the Earl of Orkney as well as the Earls of Lennox, Wigtown, Moray, Crawford, March, Angus and Stratherne. In the same year the Earl of Orkney was called to the Norwegian Riksråd to take the oath of Christopher of Bavaria who was the successor of King Eric of Denmark, Norway and Sweden. The same year the Earl of Orkney appears obtaining the patronage of the chapel of Saint Duthac in Kirkwall. in return for William quitclaiming his rights in Orkney and Shetland, an offer William accepted.

Earl of Caithness

Exchanging his inherited lordship of Nithsdale for lands in Caithness, William was granted the hereditary title Earl of Caithness in 1455.

By Lady Elizabeth Douglas he had the following children:

William Sinclair, 3rd Lord Sinclair who was reportedly disinherited by his father, only receiving Ravenscraig Castle in Fife. Lady Catherine Sinclair, who married Alexander Stewart, Duke of Albany. Lady Marjory 'Elizabeth' Sinclair (1455–80), married Andrew Leslie, Master of Rothes. With Andrew she had issue including William Leslie, 3rd Earl of Rothes

By Marjory Sutherland he had the following children:

Oliver St Clair, 12th Baron of Roslin, who received the Barony of Roslin. Alexander Sinclair George Sinclair Robert Sinclair (1447) Arthur Sinclair Lady Eleanor Sinclair (b. 1457- d. 1518), who married John Stewart, 1st Earl of Atholl. Lady Elizabeth Sinclair (b. - d. 1498), who married the Laird of Houston. Lady Margaret Sinclair , who married David Boswell of Balmuto. Lady Katherine Sinclair (b. 1440 - d. 1479) Lady Susan Sinclair Lady Mariota Sinclair Lady Euphemia Sinclair , who married John Kincaid Laird of Warriston.

Illegitimate: Sir David Sinclair of Sumburgh, died 1507.

The earl's second son of his second marriage, William Sinclair, became the designated heir of the Earldom of Caithness, and continued that title. The Barony of Roslin went to his first son by that marriage, Sir Oliver Sinclair.