Ancestral Sinclairs of Orkney & Caithness


Shared SNP


Proven R-FGC15254


Total # Likely Members

1393 A.D.



Most Interesting Affinity Family

UPDATE:  The single kit featuring under the main A2 Sinclairs of Orkney, Earldom group (here) is very interesting. They are positive for both S5246+ and FGC15253+, but negative for FGC15254-, so possibly an early split after the foundation of the St Clairs of Orkney or just before they were in East Lothian. 

Keep an eye on Craig Sinclair, Dee Spence, and Jim Wilson’s Orkney DNA website HERE >>

Download Danny Redmond’s latest chart for this lineage as of 3/9/2024:
Orkney & Caithness

Ancestral Sinclair DNA of Orkney & Caithness

The logical connection to Caithness and the Orkney islands was proven with the testing of John Archibald Sinclair, 3rd Viscount Thurso, also known as John Thurso. His “family” SNP is R-FGC35613 and he shares it with 10 others in our A2iii group. shows R-FGC35613 having a TMRCA of 225 years before present, so clearly a “family SNP” and a recent common ancestor. Backing up a step, the R-S5246 SNP shows a TMRCA of 900 ybp.

When Sir Henry Sinclair of Rosslyn married Alice de Fenton c. 1306, he was drawn first to Inverness, then to Caithness and the family became established there. Sir Henry became Baillie (tax collector) of Caithness in 1321–not an enviable job. By 1379, the Sinclairs had become earls of Orkney. (Enigmatic p. 188)

Recent Discoveries

Back in early 2019, I was in touch with the admins of the Cummings DNA project attempting to finally figure out the connection between our Caithness/Orkney Lineage and the Cummings / Comyn family. Clearly there is a connection, both in the DNA and in the written records – the narrative. At the request of the Cummings admins, I was able to get a couple people in the Caithness lineage to verify their Big Y results with Yfull. Craig Sinclair, who runs the Orkney group, got a few more to do the verification and helped to find deeper SNPs and interpret them.

This is my note to the Cummings/Comyn admins at that time:

A Sir Robert Sinclair was part of the Comyn entourage during the reign of Alexander II (1214-1249). Our best researchers can’t figure out where he came from.

William Comyn was the most powerful man at court and Robert, John, and William Sinclair were circling around him. Rondo B B Me, a terrific medievalist, thinks it most likely that Sir Robert Sinclair was a Herdmanston descendant because his name appeared in the cartulary of Soutra Hospital near to other mentions of our St Clairs of Herdmanston. Sir Robert made his first appearance there between 1190-1238 witnessing a charter to Soutra by the Graham family.

After King William died, his son became King Alexander II. William Comyn and Robert Sinclair were among Alexander’s closest companions. By about 1240, Robert Sinclair no longer appeared in the records.

Craig Sinclair tells the full story below with great detail, but I have another story first. This is a perfect example of two messages you’ve heard me repeat since Stan and I started the DNA study in 2004:

  • Don’t leap to conclusions.
  • Do the entire process, even if you don’t currently match one of the two ancestral lineages. There’s still room for many surprises, in part because I’m working diligently on England now–and that’s been pretty much ignored by family researchers due to the popularity of Scotland since the Da Vinci Code.

See the Yfull analysis and TMRCA calculations for this group.

Sinclairs in the North

by Craig Kirtland-Sinclair

St Clairs were first documented in Caithness as early as 1321 when Sir Henry Sinclair of Roslin was the Scots baillie to Caithness; then in 1364 we find Thomas Sinclair similarly employed in Orkney where he was ‘Baillie of the King of Norway’. But it wasn’t until 1379, when the St Clairs of Roslin became earls of Orkney, that this geographic location really became associated with the name St Clair and Sinclair. What is interesting, is that the lineage defining R-S5246 SNP, a subclade of S21/U106 > Z346, had been given an estimated date very close to the time that the St Clairs of Roslin became earls of Orkney in 1379; however, the “best guess” forming of this SNP has now been adjusted to 1045 A.D (Iain McDonald of Jodrell Bank).

Cummings Link

The Earldom group is very interesting because it includes a small number of members with the surname Cummings. They are positive for both S5246+, S5629+, S5632+, S5634+, S5636+, and FGC15253+, but negative for FGC15254-; so possibly an early split before the foundation of the St Clairs of Orkney, when they were barons of Roslin in Lothian.

However, YFull recently analysed 4 Cummings raw data samples and 1 McDonald whom are S5246. But there is something interesting here. One of the Cummings samples (from England, but with a papertrail back to the ‘Earnside’ branch of Cummings, who are the same patrilineal line as the ‘Altyre’ Gordon-Cummings and “the” Comyns) and McDonald split from the main Cummings cluster (which share a TMRCA during the early part of 16th century) at S5246, FGC15253 (YFull groups them S5246*), with an estimated TMRCA of 1050ybp (969 A.D.). If this age estimate holds up then it could suggest they were patrilineally Cummings as early as the 11th century, during a period of fluid surname usage.

To test this age estimate, all the earldom samples were invited to upload their Big Y raw data to YFull, and a high percentage did so. The YFull tree (July 2019) estimated that the S5246 block formed approx 950ybp (1069 A.D.), and the TMRCA for the single Cummings kit, single McDonald, Cummings cluster, and Sinclair earldom cluster, dates to approx 900ybp (1119 A.D.).

So to simplify things, there are three branches splitting off from one another at the S5246 block: 2 Cummings lines* and the Sinclair earldom line. Estimated to share a patrilineal common ancestor during the latter part of the 11th to early 12th century.

The question you may ask, with 2 lines being Cummings and another being Sinclair, were they patrilineally Cummings or Sinclair? Probability would obviously lead us to favour one over the other, that being Cummings, but both scenarios are possible. We must also consider this, that if the TMRCA was just a slightly earlier, then we are back into the period of fluid surname usage and could be looking merely at mutual origins on the Continent.

Historically, Sir Robert Sinclair (whose origins are still to be confirmed*) was part of William Comyn’s (1163-1233) entourage during the reign of Alexander II (1214-1249). Robert first appeared in charters from 1190 onwards and by 1203 he had progressed to royal court records during the reign of Alexander’s father, William the Lion, but disappeared from records after 1240. Comyn himself was one of the most powerful men at the court of King William I (reign 1165-1214) and witnessed no less than 88 of the king’s charters.

*It has been suggested, from studying charters, that Robert may have been of the Herdmanston family, and that he possibly married into the Graham family whom held lands in Pentland (including Roslin). The earliest surviving documents to place a Sinclair at Roslin dates to 1279 with Sir William Sinclair of Roslin, but this may not be when they first arrived on the land.

So the Cummings name and Sinclair are part of the same narrative within a presentable timeframe. This began with Sir Robert Sinclair in the 1190s and extended until the end of the 1200s with Sir William Sinclair of Roslin, who was also a close associate of the Comyn earls of Buchan. But the relevance of this is highly dependent on both the accuracy of the TMRCA and the paper trail of the ‘Earnside’ branch of Cummings.

Taking everything into account, the Sinclair Earldom “lineage defining” SNP is now adjusted to *FGC15254*, which has now been estimated by YFull (as dated July 2019) to have formed approximately 900ybp (1119 A.D.).

*continuing analysis will further define the S5246* group with the single Cummings and single McDonald sample. YFull is reliant on a good volume of data to enable them to accurately age SNPs and MRCAs, so it would be useful if all S5245 and S5246 Big Y testees uploaded their .BAM files for this independent NGS interpretation service.

Source:  Orkney DNA study by Craig Kirtland-Sinclair

More about the Caithness and Orkney Lineage

John, Viscount Thurso’s known lineage

John, Viscount Thurso, born John Archibald Sinclair has a genealogy that points back to the Ulbster branch of the Sinclair family who descend from George Sinclair, 4th Earl of Caithness (c.1529 – 1582). This earl was married to Lady Elizabeth Graham, daughter of the Earl of Montrose and wife Janet Edmonstone(2). The 4th Earl of Caithness and Lady Graham had 7 children. Their second child was William Sinclair, first Laird of Mey, who left no legitimate children, but did leave two illegitimate sons, Patrick (who had no heirs) and John. This John had children and thus founded our Ulbster line. These illegitimate sons, Patrick and John, had two different mothers – Margaret Mowat and Lucy, daughter of Gordon of Gight.(3, p.248) Isn’t it interesting that the Mowat name was among the witnesses of the gift of Roslin and Catcune to William Sinclair? Unfortunately, there appears to be no Mowat DNA study as of this writing.

According to the written records, the line of Sinclair earls of Caithness was founded by Sir William Sinclair, earl of Caithness (c. 1408 – 1480). He was also baron of Roslin, descendant of the first known Sinclair of Roslin, Sir William Sinclair sheriff of Edinburgh (d. 1299).

The Rosslyn Connundrum

Father Richard Augustus Hay, Roland William Saint Clair, and others who have studied our family arrived at differing conclusions about the origins of our Roslin family in Scotland. You see, it’s impossible to be certain with the complete absence of documents on the origins of the Roslin family. Many researchers state that they received Roslin from King David I, but recent unbiased researchers have stated that no record exists of this land grant.

The first known Sinclair into Scotland was Henry St Clair of Herdmanston c. 1162 who received Herdmanston from Sir Richard de Morville and also Carfrae, but there is no documented proof that the two families are connected.

This from Peter Sinclairs research – “There were a few early charters witnessed by men with the title of ‘de Roscelyn’ or Roslin but the first mention of a St. Clair in connection with the barony of Roslin was when Henry de Roscelyn resigned his barony back to the King, who then gifted the lands to William de St. Clair. The Roslin charter is dated 14 September 1279 and one of the witnesses to that charter interestingly, was William Comyn of Kilbride, continuing the Comyn connection.”

There is, however, a Henry of Roslin who resigned the land of Roslin(4) to King Alexander III in 1279. The king then granted them to William Sinclair, knight, the first documented Sinclair at Roslin. No one is quite sure who Henry of Roslin was.

14 September 1279, Traquair – “Alexander, king of Scots, gives notice that, since Henry of Roslin, tenant of his lands of Roslin (MLO) and Catcune (nr Borthwick, MLO), has resigned and quitclaimed these lands to him by rod and staff, he has given to William Sinclair, knight, said lands of Roslin and Catcune, doing service of half a knight” (4)

The witnesses to this grant of land might be informative:
Robert Wishart, bishop of Glasgow (d.1316)
William Fraser, bishop of St Andrews (d.1297)
Gilbert de Umfraville, earl of Angus (d.1307)
William Comyn of Kilbride (d.c.1283)
Simon Fraser (d.1291×92)
Bernard Mowat (son of Michael)
William Bisset, knight (late 13C)
Patrick Graham, knight (d.1296)


There are three names of great interest in that list of witnesses – Umfraville, Comyn (Cumming), and Bisset. Of those, the surname Cumming were showing up even before we had Big Y testing – on the list of Z346* Z343- SNP matches for the Caithness Lineage.

That surname Umfraville (Humphrey) is interesting to me as it shows up in Northamptonshire, England where St Clairs, de Morville and the de Vaux family held land. Yet we see no DNA matching with Umfraville, Moreville, or Vance (Vaux) families in our Caithness / Orkney Lineage.


Newbattle Registrum, Cartae originales, no. 6 – RRS, iv, no. 126

Sinclair, Peter “St. Clair / Sinclair” website accessed January 30, 2021

2 – Website “The Peerage” A genealogical survey of the peerage of Britain as well as the royal families of Europe –

3 – Saint-Clair, Roland William, The Saint-Clairs of the Isles, being a History of the Sea-Kings of Orkney and their Scottish Successors of the Sirname of Sinclair,” H. Brett, General Printer and Publisher, Shortland and Fort Streets, Auckland, N.Z., 1898.

4 – People of Medieval Scotland website