John Macdonald, first Lord of the Isles, married Margaret, daughter of Robert II, and had by her Donald, his successor. Donald, second Lord of the Isles, married Margaret Leslie, by whom he had Alexander, Angus and Mariot.
Alexander Sutherland of Dunbeath married Mariot, daughter of Donald of the Isles, and had by her Marjory and others.
William St.Clair, first Earl of Caithness, married as his second wife, Marjory, daughter of Alexander Sutherland of Dunbeath, and had by her William and other children. He gave the earldom of Caithness to William in 1476.
William Sinclair, second Earl of Caithness, married Mary Keith, by whom he had two sons: John, his successor, and Alexander, first of Dunbeath and Stemster. He was killed at the battle of Flodden in 1573. About three hundred of his followers fell with him. He was the first chief of the Sinclairs of Caithness considered as a Highland clan.
John, second earl, invaded Orkney in 1529 with five hundred men, and was killed at the battle of Summerdale. The most of his followers perished with him. He was succeeded by his son, George.
George, sixth earl, was appointed justiciar of Caithness in 1566. He married Elizabeth, daughter of William Graham, Earl of Montrose, and had by her three sons: John Garbh, Master of Caithness ; William, first of Mey; and George, second of Mey. He was a wily and ambitious man. He turned against John Garbh, his heir, and imprisoned him in Girnigo castle, where he was murdered in 1576. The fourth earl died in 1582.
John Garbh married Jean, daughter of Patrick Hepburn, Earl of Bothwell, and had by her three sons: George, James of Murkle, and John of Rattar. George succeeded his grandfather.
James of Murkle was succeeded by his son Sir James. Sir James had two sons, John and David of Broynach.
John became Earl of Caithness in 1785. David of Broynach was married twice. He had one son, James, by his first wife; and two sons, Donald and David, by his second wife. Donald had a son named William, who was tacksman of Isauld from 1755 to 1760. The Rev. John Sinclair, Kinloch-Rannoch, is descended from William and claims to be the representative of the Sinclairs of Broynach.
William, first of Mey, had two sons, Patrick and John, both of whom were legitimated in 1607. John was the progenitor of the Sinclairs of Ulbster.
Sir John, eighth of Ulbster was a man of great ability and energy. He was created a baronet in 1786. He raised the Rothsay and Caithness Fencibles in 1794, and the Caithness Highlanders in 1795. He published several valuable books, and hundreds of pamphlets. He died in 1835.
George, second of Mey, had three sons: William, John of Geanies, and Alexander of Latheron.
James, fourth of Mey, was created a baronet in 1631. He had three sons: William, Robert of Durran, and George of Olrick.
James, third of Durran, had a son named George. John Sutherland Sinclair, son of this George, was a lieutenant-colonel in the army.
George, fifth earl of Caithness, married Jean, daughter of George Gordon, fifth earl of Huntly, and had by her two sons: William, known as Lord Berriedale, and Francis of Northfield.
John, son of Lord Berriedale, signed the National Covenant in 1635, and supported the cause of Presbyterianism and civil liberty most loyally. He died in 1639, leaving one son, George. Francis of Northfield married Elizabeth Fraser, by whom he had George of Keiss.
George, the fifth earl, died in 1643. He was Earl of Caithness for the long period of sixty-one years. He is known in history us the Wicked Earl.
He was succeeded by his great-grandson, George, son of John, son of William. George, the sixth earl, died without issue in 1676. He was deeply in debt and sold his estates to John Campbell of Glenurchy, afterwards Earl of Breadalbane. He also tried to convey the title of Earl of Caithness to Glenurchy. He was not a wicked earl, but he was a very foolish earl.
George Sinclair of Keiss was an active and patriotic man. He had a bitter struggle with Campbell of Glenurchy for some of the lands which the latter claimed, and also for the title of Earl of Caithness. In 1681 the Privy Council acknowledged his right to the lands of Northfield, Tister, and Keiss, and also to the title of Earl of Caithness. He died without issue in 1698, and was succeeded by John Sinclair, third of Murkle. John, the eighth earl, died in 1705, and was succeeded by his son Alexander.
Alexander, the ninth earl, was born in 1654. With amazing indifference to the interests of his clan, he willed his estates to George Sinclair, Lord Woodhall, a man who had no connection with the Sinclairs of Caithness. He died in 1765.
William Sinclair, sixth of Rattar, was acknowledged Earl of Caithness in 1768, and confirmed in his claim to that title in 1772. He was the tenth earl. He died in 1779 and was succeeded by his son John. John, the eleventh earl, died unmarried in 1789 and was succeeded by Sir James Sinclair, tenth of Mey.
James of Mey, the twelfth earl, died in 1825 and was succeeded by his son Alexander.
Alexander, the thirteenth earl, died in 1855, and was succeeded by his son James.
James, the fourteenth earl, was noted for his scientific attainments. He died in New York in 1881, and was succeeded by his son George.
George of Mey, the fifteenth earl, died unmarried in 1859. He was succeeded in the title of earl, but not in his estate, by James Augustus Sinclair, son of Lieut-Colonel John Sutherland Sinclair of the Durran family.
James Augustus, the sixteenth earl, was for a number of years agent in Aberdeen for the bank of Scotland. He married in 1855, Janet, daughter of Dr. Roderick Macleod in London, and had by her John Sutherland and other sons. He died in 1891.
John Sutherland Sinclair, seventeenth Earl of Caithness, was born in 1S57. He was educated at the University of Aberdeen. He emigrated to the United States. He has a farm called Berriedale at Lacota in North Dacota. He has no land in Scotland. But that is not a matter of any great consequence; he is chief of the Sinclairs of Caithness.
ARE THE SINCLAIRS A HIGHLAND CLAN ?
As the Normans and the Lowlanders had a good deal of Keltic blood in their veins, it would be folly to look upon the Lords of Roslin as Scandinavians.
Sir Henry Sinclair, fourth of Roslin, was the son of a Keltic mother. William Sinclair, second Earl of Caithness and progenitor of the Sinclairs of Caithness, was also the son of a Keltic mother.
Author's Correction (2nd Edition 1902):
for a Keltic mother read a mother with a large share of Keltic blood.
The Scandinavians who settled in Caithness occupied only parts of the country. They did not slay the whole of the original inhabitants. It was indeed quite a common thing for a Norwegian to marry into a Keltic family.
Leod, the progenitor of the Macleods, was the son of a Scandinavian father. He married a Highland girl and had two sons by her, Torquil of Lewis and Tormod of Dunvegan. These sons were only half Scandinavians.
Tormod of Dunvegan married a Keltic girl and had a son named Malcolm by her. Malcolm was very far from being a half Scandinavian. He was certainly a Kelt rather than a Scandinavian.
Before a Sinclair, a Macleod, or a Gunn talks about his Scandinavian origin, it would be wise for him to calculate with some degree of care to what extent his blood is Scandinavian blood.
Patrick Sinclair, third of Ulbster, was the son of Jane Chisholm. John, fourth of Ulbster, was the son of Elizabeth Mackay. John, fifth of Ulbster, was the son of Janet Sinclair. John, sixth of Ulbster, was the son of Jane Munro. George, seventh of Ulbster, was the son of Henrietta Brodie.
Sir John Sinclair, eighth of Ulbster, the most eminent man that Caithness ever produced, was the son of Janet Mackay.
Author's Correction (2nd Edition 1902): for Janet Mackay read Janet Gordon.
Was Sir John a Scandinavian ? He believed himself that he was a Highland chieftain.
The Gaelic form of the name Sinclair is Singlear.
The Sinclairs of Argyleshire call themselves Clann-na-Cearda, or the children of the craft or trade. It is probable that this name was given them by their neighbours, who would naturally take for granted that Singlear meant shingler or flax-dresser. The Sinclairs of Argyleshire are out-and-out Highlanders.
The Earls of Caithness held their lands of the Crown, and were in no way subject to the Saintclairs of the Lowlands. They lived in the Highlands, they were chiefs of the Sinclairs of Caithness, they ruled over a large number of Gaelic-speaking Highlanders, and they were to some extent Kelts by blood. They had thus a perfect right to regard themselves as Highland chiefs and to wear tartans and bonnets, and use bag-pipes, if they saw proper. The Sinclairs of Caithness are thus a Highland clan just as much as the Sutherlands, Gunns and Macleods are Highland clans; but they are not Kelts to the same extent.
Author's Addition (2nd Edition 1902):
The full-dress tartan of the Sinclairs has a large proportion of red in it. The hunting tartan has also a good deal of red in it, but the chief colour in it is green. It is a very handsome tartan. The badge of the Sinclairs is clover. Whin or furze is also used.
The motto of the Earls of Caithness is "Commit thy work to God".