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. Provided by Wikipedia