Sun History, Family Crest & Coats of Arms
The Sun surname was a Norman habitation name, derived from when families lived at St. Clai-sur-Elle in La Manche and in St-Clair-L'Evêque in Calvados, Normandy where the site of the seignorial castle is still discernible. 
Early Origins of the Sun family
The surname Sun was first found in the barony of Roslyn, Midlothian where King Alexander I of Scotland granted a parcel of land to William de Sancto Claro in 1162. They were originally from St Clare, Pont d'Eveque, Normandy, and are descended from Walderness Compte de Saint Clare who arrived in England with William the Conqueror.
"Wace mentions the Sire de St. Clair at Hastings. This was Richard de St. Clair who held lands, Suffolk, 1086, "  The Domesday Book also notes that Britel de St. Clair, brother of the aforementioned Richard de St. Clair held lands in Somerset. Britel's son William de St. Clair held lands in Dorset in 1130.
Despite these early records in England, the name is more often than not associated with Scotland. For it is there that the name excelled both in numbers and power. "The first Sinclairs in Scotland appear to have been vassals of the great territorial magnates, de Morville. Their first possession in Scotland was the barony of Roslin, near Edinburgh, which they held in the reign of David I (1124-1153). The earliest bearers of the name appear in charters connected with the abbeys of Dryburgh and Newbattle, the Hospital of Soltre (now Soutra in Midlothian), the church of Glasgow, etc." 
Sir Henry Sinclair fought with King Robert the Bruce at Bannockburn, and helped assure the independence of the Scottish Kingdom. Sir Henry's son married Isabel, the heiress of the earldom of Orkney, and their son became the senior Earl of Norway. The Clan achieved great status having married into both Norwegian and Scottish royalty.
Back in England, the name prospered as well as The Hundredorum Rolls of 1273 confirms: John de Sanet Claro in Suffolk; Robert de Sancto Claro in Somerset; and William de Sancto Claro in Kent. 
Over in Somerset, from the first listing above, Richard Seinteclere and William Seyncler were both listed in Kirby's Quest. 
Early History of the Sun family
This web page shows only a small excerpt of our Sun research. Another 189 words (14 lines of text) covering the years 1470, 1455, 1607, 1345, 1400, 1696, 1582, 1566, 1643, 1566, 1576, 1566, 1610, 1676, 1683, 1750 and are included under the topic Early Sun History in all our PDF Extended History products and printed products wherever possible.
Sun Spelling Variations
Spelling variations of this family name include: Sinclair, Saint Clare, Sancto Claro, Singular, Sinclaire, Seincler, Sanclar, Sincklair, Sinclear, Sincler and many more.
Early Notables of the Sun family (pre 1700)
Notable among the family at this time was Henry I Sinclair, Earl of Orkney, Baron of Roslin (c. 1345-1400), Scottish and a Norwegian nobleman; Prince of Orkney, 3rd Earl of Orkney; and George Sinclair or Sinclar (d. 1696), a Scottish mathematician, engineer and demonologist, the first Professor of Mathematics, Glasgow, probably a native of East Lothian.
Other notables include: George Sinclair fourth Earl of Caithness (d. 1582), second, but eldest surviving, son of John, third Earl of Caithness; and George Sinclair, fifth Earl...
Sun World Ranking
In the United States, the name Sun is the 4,349th most popular surname with an estimated 7,461 people with that name.  However, in Canada, the name Sun is ranked the 547th most popular surname with an estimated 8,943 people with that name.  And in Australia, the name Sun is the 797th popular surname with an estimated 4,921 people with that name.  New Zealand ranks Sun as 787th with 926 people. 
Migration of the Sun family to Ireland
Some of the Sun family moved to Ireland, but this topic is not covered in this excerpt.
Some of the first settlers of this family name were:
Sun Settlers in United States in the 19th Century