Lord Chief Justice of Scotland and Admiral of the Seas
http://www.mids.org/sinclair/who/henry.html
The name Sinclair is of Norman origin. The family surname originated from its home in the town of Saint-Clair-sur-l'Epte in Normandy. The family took its surname from this town and was one of the first families to use the surname form. The family was established in Scotland in 1162 when Henry de St Clair of Roslin was granted lands in Lothian. His descendant Sir William became guardian to the heir of Alexander III and gained the Barony of Rosslyn in 1280.
http://www.tartans.com/clans/Sinclair/sinclair.html
http://www.tartans.com/articles/famscots/sinclairh.html
http://kingcrest.com/sinclair/
http://hometown.aol.com/ttrim36387/douglas.htm
http://www.mids.org/sinclair/who/rollo.html
Se puede ver el mapa de Zeno, en base al cual Henry Sinclair fleto una flota de 13 barcos a America c. 1398 en http://egla.bok.hi.is/cgi-bin/zoom.cgi?language=english&id=18&std=3

There is compelling evidence to confirm that in 1398, Prince Henry travelled in the wake of his Viking forebears to the New World . Almost 100 years before Columbus is reported to have discovered America, Prince Henry had sailed with an armada of 12 ships, fully crewed and with 200 hundred men-at-arms on board for better protection of the fleet.  There is evidence from early maps and from reading the ‘Zeno’ narrative, that Prince Henry was accompanied by fellow Knights Templar, and by Cistercian (farming) monks. After an unsuccessful attempt to land in Markland (Newfoundland) they decided to sail on to Estotiland (Nova Scotia).  Five ships were lost, and another two so badly damaged that they had to be abandoned but not before they had been stripped of all valuable materials-including cannon.  As a Venetian cannon of the 14th Century was dredged up from the harbour of Louisburgh on Cape Breton Island, it is likely that this was the place where Henry first landed in the New World.  The Zeno map, which was the most accurate of its day, would tend to confirm this conclusion.  The ‘Jarldom’ of Orkney remained in Sinclair hands until the Northern Isles were handed over to James III of Scotland, as part of the dowry, of Princess Margaret of Denmark in 1471.  Thereafter, the Sinclair influence shifted south to Caithness where Prince Henry’s grandson, William, had already been made Earl in 1454.
http://www.caithness.org/caithnessfieldclub/bulletins/1999/castle_sinclair_girnigoe_history_of_clan_sinclair.htm