St Clair and Sinclair carry the same Norman surname into Scottish history. Rosslyn Chapel, founded by William St Clair in 1446, gives the older spelling a lasting place in the landscape. Records also preserve St. Clair and other variants, making the written form an important part of researching this family name.
Browse Sinclair and St Clair Family Crest gifts, choosing the spelling that belongs in your family.
This article covers the St Clair and St. Clair form. Our separate history of Clan Sinclair takes the Sinclair spelling and the clan structure attached to it. Almost everything below applies to both, because they are one name written two ways.
Where Does the Name St Clair Come From?
St Clair is a Norman territorial surname, taken from a place called Saint-Clair. The Dictionary of American Family Names, reproduced by FamilySearch, identifies Saint-Clair-sur-Elle in Manche. The Rosslyn family account connects its origins with Saint-Clair-sur-Epte. These different identifications sit within the same broad history of a Norman place-name carried into Britain. The Latin form de Sancto Claro appears in historical records; Sinclair developed as the contracted form of the name.
Territorial surnames of this Norman type are common in Scotland, and our survey of Norman-descended Scottish families shows how the pattern worked.
How Did the St Clairs Reach Scotland?
By the ordinary Norman route, and then by charter. Saint-Clairs appear in England straight after 1066: Richard and Brittel of Saint-Clair are both in Domesday Book. Scottish tradition holds that William of Saint-Clair came north with Saint Margaret in 1068 and received the barony of Roslin for it. This belongs to the family's foundation tradition; the later charters provide firmer dates for tracing its Scottish estates.
The record starts a century later. Henry of Saint-Clair held a charter for lands at Herdmanston in Haddingtonshire in 1160, among the earliest firmly documented Sinclairs or St Clairs in Scotland. The Roslin line is solid from 1280, when William St Clair, sheriff of Edinburgh, was granted the barony, and from there the family is continuously documented.
Roslin's other claim on Scottish history came in 1303, when a Scottish force won a winter fight below the castle, covered in our account of the Battle of Roslin. The castle has its own history in our piece on Rosslyn Castle, and the wider Norman building effort in our guide to castles raised by Norman families.
St Clair or Sinclair: Are They the Same Family?
Yes. Sinclair became the more widespread form in Scottish records, but the separated spelling continued.
Sinclair is a contraction of Saint Clair, the two words run together and worn down by four hundred years of Scots speech. Both forms were in use side by side for centuries, sometimes within one household. Barry Griffin's surname indexes of the 1901 Scottish census list 12,896 entries for Sinclair and 34 for the exact indexed form Stclair. The latter figure is not a combined count of every spaced or punctuated St Clair variant.
The separated form survived better among landed lines with reason to keep the older written style, and better again overseas, where an emigrant clerk was as likely to write what he saw as what he heard. The Earls of Rosslyn, who own the chapel, still carry the compound surname St Clair-Erskine, taken up after the earldom passed to the Erskines in 1805. The practical lesson is never to search one spelling alone.
Who Were the Earls of Orkney and Caithness?
The northern earldoms are where this family stops being one more Lowland barony and becomes a power in the North Sea.
Henry Sinclair, born about 1345, claimed the earldom of Orkney through his mother and was invested by Haakon VI of Norway at Marstrand on 2 August 1379. Orkney was then Norwegian, so the earls held it as vassals of a foreign crown, which gave them extraordinary independence and eventually cost them the title: the earldom was resigned by order of James III after Orkney passed to Scotland.
The two earldoms overlapped before the island title was surrendered. William Sinclair, Baron of Roslin and third Earl of Orkney, was High Chancellor of Scotland from 1454 to 1458 and received the earldom of Caithness in 1455. In 1470 the compensation for relinquishing Orkney and the lordship of Shetland was Ravenscraig Castle, as Historic Environment Scotland explains. The chief of the name today is Malcolm Sinclair, 20th Earl of Caithness. The northern world this family worked in appears in our survey of the clans of Caithness and the far north, alongside neighbors such as the Gunns, and the Orkney end of it appears in our history of the Drever name and the 1468 pledge.
Who Built Rosslyn Chapel, and When?
William St Clair founded Rosslyn Chapel in 1446. That is the date used by Rosslyn Chapel Trust, and the one to use when placing his church within the family chronology. Construction continued over subsequent decades, so the foundation and the completion of particular parts of the building are different events.
The building was dedicated to Saint Matthew and intended as a collegiate church with choir, nave and transepts. Only the choir was finished. St Clair died in 1484, and his son roofed what existed with its stone vault rather than completing the plan. What survives is a fragment, which is why it feels so dense: a cathedral's worth of carving compressed into one end of an unfinished building.
Its most famous feature, the Apprentice Pillar, was originally the Prince's Pillar. The apprentice story, in which a master mason kills the boy who carved it better than he could, is an eighteenth-century legend attached to an older object.
What About the Templars, the Grail and the Voyage to America?
Rosslyn's later legends form a different strand of its story from the medieval church and the records of its founders. Keep the two in view when reading about the chapel: the imaginative afterlife helps explain its fame, while the surviving building and documents explain its history.
Rosslyn attracts three recurring claims. The first is that the chapel was built by or for the Knights Templar and conceals Templar treasure or the Holy Grail. Medieval historians say these accounts have no basis in fact; the historian Louise Yeoman's position is that William St Clair built the chapel so Mass could be said for the souls of his family, which is what collegiate churches were for. The awkward detail is that members of this very family gave evidence against the Templars at their trial in Edinburgh in 1309.
The second is that the carvings are Masonic and encode a secret lineage. The researcher Robert L. D. Cooper has pointed out the chronology problem: the third degree of Freemasonry was devised around 1720, nearly three centuries after the founding, and the overtly Masonic carvings appear to have been added during restoration in the 1860s by an architect who was himself a Freemason.
The third is that certain carvings show American maize and aloe, proving that Earl Henry Sinclair crossed the Atlantic before Columbus. The botanist Adrian Dyer examined them and concluded they are stylized decorative patterns that only coincidentally resemble real plants. The voyage itself rests on identifying Henry with a figure called Zichmni in letters attributed to the Zeno brothers of Venice. Most historians regard the Zeno material as a hoax, and the identification with Sinclair has not been accepted. These transatlantic stories took their modern form in the early 1990s.
The chapel's own account of The Da Vinci Code describes how the 2003 novel and its film adaptation brought new visitors. That modern cultural story belongs alongside the architecture, conservation and continuing worship, without turning the novel's plot into a medieval event.
Who Was Arthur St. Clair?
The strongest American hook this surname has, and a Caithness man.
Arthur St. Clair was born at Thurso on 23 March 1737, probably the son of a merchant named William Sinclair and Elizabeth Balfour. The change from Sinclair to St. Clair happens right there, inside one lifetime: this surname's spelling history in miniature.
He bought a commission in the Royal American Regiment in 1757 and came over for the French and Indian War, serving at Louisbourg in 1758 and at the Plains of Abraham. He resigned in 1762, settled in the Ligonier Valley in Pennsylvania and became the largest landowner west of the Alleghenies.
In the Revolution he took a colonel's commission with the 3rd Pennsylvania in January 1776, crossed the Delaware with Washington that December and fought at Trenton and Princeton. Promoted major general in 1777, he commanded Fort Ticonderoga and had to abandon it in July. Court-martialed and exonerated in 1778, he continued in service. The National Park Service records him commanding Pennsylvania brigades at Jockey Hollow in the winter of 1779–80 and becoming commander of the United States Army in 1791.
On 2 February 1787 Congress elected him its President for a one-year term, during which the Northwest Ordinance passed. From 15 July 1788 to 22 November 1802 he governed the Northwest Territory, covering what became Ohio, Indiana, Illinois, Michigan, Wisconsin and part of Minnesota. He named Cincinnati, and in 1790 created St. Clair County, naming it after himself; it was the first county in present-day Illinois.
On 4 November 1791, near what is now Fort Recovery, his army was destroyed by a confederation led by the Miami chief Little Turtle and the Shawnee chief Blue Jacket. More than 600 soldiers were killed, and it remains the heaviest defeat United States forces have suffered against Native American opponents. An inquiry cleared him, but he surrendered his commission in March 1792 at Washington's request, and Jefferson removed him as governor in 1802. He died in poverty at Greensburg, Pennsylvania, on 31 August 1818. The wider Scottish contribution to the founding is set out in our piece on Scottish philosophy and the Declaration of Independence.
How Should a St Clair Line Be Traced?
- Search Sinclair and St Clair together from the first query, with St. Clair, Stclair and Saintclair added. Indexes treat the space and the period inconsistently, so try the name with and without both.
- Work Caithness, Orkney and Midlothian as the three Scottish heartlands. Our history of the Budge name in Caithness gives a sense of the northern record landscape.
- Expect American lines to prefer St. Clair with the period, on the pattern Arthur St. Clair set. That is a scribal habit, not evidence of a separate family.
- Compare register images with index transcriptions on ScotlandsPeople: a clerk's Sinclair and a clerk's St Clair can be the same hand a page apart.
- Do not assume descent from the Roslin or Caithness lines. Build the connection through parents, spouses, places and dated records, one generation at a time.
Own a Piece of St Clair Heritage
Choose a St Clair Family Crest mug for everyday use, a framed ornament for the holiday tree or a St. Clair garden flag for the family home. Each uses a tartan background, with the spelling and crowned crest design shown in the product photographs. The shared Sinclair collection makes it easy to compare the two written forms while keeping the name on your gift personal to its recipient.
Frequently Asked Questions About the St Clair Name
Are St Clair and Sinclair the same surname?
Yes. Sinclair is the contracted form of Saint Clair, and both spellings were used in Scotland for centuries. The name is Norman French in origin and Scottish by settlement. For genealogy, search the contracted, spaced and punctuated forms together; census indexes may keep them separate.
Did the St Clairs build Rosslyn Chapel for the Knights Templar?
No. It was founded as a collegiate church dedicated to Saint Matthew, so Mass could be said for the founder's family. Medieval historians find no basis for the Templar accounts, and members of the family testified against the Templars in Edinburgh in 1309.
Did Henry Sinclair reach America before Columbus?
The voyage is not established history. The claim rests on identifying him with a figure in the Zeno letters, which most historians regard as a hoax, and on carvings a botanist found to be stylized patterns rather than American plants.
Was Arthur St. Clair born in Scotland?
Yes, at Thurso in Caithness on 23 March 1737. He served in the British Army before the Revolution, presided over the Continental Congress in 1787 and governed the Northwest Territory to 1802.
Reading the Spelling in Family Records
Start with the form used by your closest known ancestor, then repeat the same search with the common alternatives. Record the spelling exactly as it appears on a birth, marriage or death entry, alongside the date and place. When a person appears under two spellings, compare the other details before deciding that the entries belong together. A spouse, occupation, street or named witness can be more revealing than the spaces in the surname.
Keep a short timeline for each household. This makes it easier to distinguish people of the same name and to follow a family moving between parishes or across the Atlantic. An index is a finding aid; the image of the record preserves details that a search result can omit. The result is a family history built around identifiable people, with the wider Sinclair and St Clair story supplying its Scottish setting.
Sources and Further Reading
- Canmore: Roslin Chapel, site 51812 — the parish of Lasswade, construction from about 1446 at Sir William St Clair's instruction, and the unfinished choir.
- Rosslyn Chapel: history — the chapel trust's own account, founded 1446, and the founder's death in 1484.
- Rosslyn Chapel — the Apprentice Pillar and scholarly responses to the Templar, Masonic and maize claims.
- Henry Sinclair, Earl of Orkney — the 1379 investiture by Haakon VI, and why historians reject the Zichmni identification and the Zeno letters.
- Clan Sinclair — de Sancto Claro, the Herdmanston charter of 1160, the Roslin barony of 1280, and the Caithness earldom of 1455.
- Arthur St. Clair — Thurso 1737, the Continental Congress presidency, the Northwest Territory governorship, and the defeat of 1791.
- St. Clair County, Illinois — created by his own proclamation in 1790 and named after himself.
- Earl of Rosslyn — how the St Clair name joined Erskine, and the family's continuing ownership of the chapel.
- Sinclair in the 1901 Scottish census — 12,896 bearers, ranked 50th.
- Stclair in the 1901 Scottish census — 34 bearers, ranked 5,989th.
- ScotlandsPeople — National Records of Scotland registers and census images for every spelling of the name.
- Dictionary of American Family Names, via FamilySearch: the Norman surname origin.
- Historic Environment Scotland: Ravenscraig Castle: the 1470 exchange.
- National Park Service: people at Morristown: Arthur St. Clair’s continuing military commands.
- Clan Sinclair USA: hereditary chief.
- Rosslyn Chapel: The Da Vinci Code: modern fiction and the chapel.