Henry I Sinclair, Earl of Orkney, Baron of Roslin (13451400) was a
Scottish and a
Norwegian nobleman. Sinclair held the title
Earl of Orkney under the
King of Norway (see Earl of Orkney: Scottish Earls under the Norwegian Crown). He is sometimes identified by another spelling of his surname,
St. Clair. He was the grandfather of
William Sinclair, 1st Earl of Caithness, the builder of
Rosslyn Chapel. He is best known today because of a modern legend that he took part in explorations of
Greenland and
North America almost 100 years before
Christopher Columbus. William Thomson, in his book
The New History of Orkney, wrote: "It has been Earl Henry's singular fate to enjoy an ever-expanding posthumous reputation which has very little to do with anything he achieved in his lifetime."