No certain record exists but it is likely that the Sinclairs came from
Saint-Clair-sur-Epte in
Normandy. According to traditional history, William of Saint-Claire accompanied
Saint Margaret of Scotland, daughter of
Edward the Exile to
Scotland in 1068, where she eventually married
Malcolm III of Scotland. In return for his efforts, the king supposedly granted Sinclair the barony of Roslin "in free heritage". However, according to late 19th century historian Roland Saint-Clair, it is not known if the people who held the estate of Roslin before
William St. Clair (died 1297), who is by tradition the 6th Baron, were actually of the same surname, and that he arrived in Scotland from Normandy in the 13th century.
William Sinclair (died 1480) who was the 11th Baron of Roslin was also the 3rd
Earl of Orkney, 1st
Earl of Caithness and 2nd
Lord Sinclair. He divided his estates: his eldest son from his first marriage,
William, inherited the title of Lord Sinclair, while he left the Barony of Roslin to his eldest son from his second marriage,
Oliver, and the earldom of Caithness to his second son from his second marriage, another
William, from whom descend the chiefs of the
Clan Sinclair. The family of Roslin or Rosslyn prefer the spelling "St Clair" whilst the family of Caithness prefer the spelling "Sinclair". Although the
Rosslyn Chapel tourist website refers to the early Barons by the spelling of Rosslyn, most historic sources refer to them by the spelling of Roslin which is also used for the castle. The later
Earls consistently appear with spelling of Rosslyn in accordance with the name of the chapel. The Rosslyn Chapel tourist website also refers to several of the early Barons as Princes of Orkney,
Herdmanston in
East Lothian had been held from the 12th century, when Henry St Clair received a grant of the lands of Herdmanston, from
Richard de Morville, Constable of Scotland. However, according to the website clansinclairusa.org, William St Clair of Roslin was probably unrelated to the St Clairs of Herdmanston. According to Archibald Allan writing in 1900, Henry St Clair of Herdmanston appears to have been a son of the first William de St Clair of Roslin of the 11th century, but this William's existence cannot be proved by contemporary evidence and according to Roland Saint-Clair, William St. Clair who died in 1297 was the first proven Baron of Roslin. ==Barons of Roslin==