James FitzJames, 1st Duke of Berwick
James FitzJames, 1st Duke of Berwick, 1st Duke of Liria and Jérica, 1st Duke of Fitz- James( 21 August 1670 – 12 June 1734) was an Anglo- French military leader, illegitimate son of King James II of England by Arabella Churchill, sister of the 1st Duke of Marlborough.
Berwick was a successful general in the pay of Louis XIV of France.
William Douglas, 1st Marquess of Douglas
William Douglas, 1st Marquis of Douglas and 11th Earl of Angus( 1589 – 1660) was a Scottish nobleman.
James Douglas, 1st Lord Dalkeith
James Douglas, 1st Lord Dalkeith( after 1372 – before 22 May 1441) was a Scottish nobleman born in Dalkeith, Midlothian, Scotland to Sir James Douglas and Agnes Dunbar.
James was the brother of Nicholas Douglas, 1st Lord of Mains.
Lord Dalkeith descended from Andrew Douglas of Hermiston( or" Herdmanston")( d.b. 1277), younger son of Archibald I, Lord of Douglas( fl. c. 1198 – 1238).
Andrew was succeeded by his son William Douglas of Hermiston, a signatory of the Ragman Roll in 1296.
William of Hermiston's son, James Douglas of Lothian succeeded his father and produced two sons, Sir William Douglas and Sir John Douglas.
Sir William Douglas, known as the" Knight of Liddesdale" or the" Flower of Chivalry" obtained the privileges of the barony of Dalkeith, in Midlothian, in 1341, and the barony of Aberdour, in Fife, in 1342.
Following the Flower of Chivalry's murder at the hands of his godson William Douglas, 1st Earl of Douglas, both baronies passed to his nephew, James.
James Douglas was confirmed in this position when his title was ratified by the Earl of Douglas prior to 1370.
The lands of Dalkeith, and Aberdour, in Fife, were combined as a single barony in 1386, with the principal seat at Dalkeith Castle, and a secondary residence at Aberdour Castle.
He married Elizabeth( Princess)
Stewart, daughter of King Robert III, about the year 1387.
They had five children before she died: William, James, Henry, Janet( who married John Hamilton of Cadzow) and Margaret.
He married, as his second wife, Janet Borthwick, daughter of Sir William Borthwick, with whom he had a son named William.
Sonny Curtis
Sonny Curtis( born May 9, 1937) is an American singer and songwriter.
Most of his work falls into the pop and country genres.
He was a teenage friend and band member with Buddy Holly in Lubbock, Texas.
Francis Douglas, 1st Baron Douglas of Barloch
Francis Campbell Ross Douglas, 1st Baron Douglas of Barloch KCMG( 21 October 1889 – 30 March 1980), was a British journalist, solicitor and Labour Party politician.
Archibald Douglas, 4th Earl of Douglas
Archibald Douglas, 4th Earl of Douglas, Duke of Touraine( c. 1369 – 17 August 1424), was a Scottish nobleman and warlord.
He is sometimes given the epithet" Tyneman"( Old Scots: Loser), but this may be a reference to his great- uncle Sir Archibald Douglas.
James Douglas, 7th Earl of Douglas
James Douglas, 7th Earl of Douglas, 1st Earl of Avondale( 1371 – 24 March 1443), latterly known as James the Gross, and prior to his ennoblement as James of Balvenie, was a late mediaeval Scottish magnate.
He was the second son of Archibald Douglas, 3rd Earl of Douglas and Joan Moray of Bothwell and Drumsargard( now Cambuslang), d. after 1408.
William Douglas, 1st Earl of Douglas
William Douglas, 1st Earl of Douglas( c.1323 – 1 May 1384) was a Scottish nobleman, peer, and magnate.
Archibald Douglas of Glenbervie
Sir Archibald Douglas of Glenbervie( 1513 – 18 September 1570) was a Scottish nobleman.
Archibald Douglas, 1st Duke of Douglas
Archibald Douglas, 1st Duke of Douglas( 15 October 1694 – 21 July 1761) was a Scottish nobleman.
He was the second son of James Douglas, 2nd Marquess of Douglas, by his second marriage.
His elder brother, William, died in infancy in 1694, and Archibald was thereafter styled Earl of Angus.
Douglas succeeded his father in 1700, and on 10 April 1703, was created Duke of Douglas, Marquess of Angus and Abernethy, Viscount of Jedburgh Forest, and Lord Douglas of Bonkill, Prestoun, and Robertoun.
The bearer of the Crown of Scotland on state occasions, he conveyed it to Edinburgh Castle after the closing of the last Parliament of Scotland.
During the Jacobite rising of 1715, Douglas took the Hanoverian side, and led the volunteer horse at the Battle of Sheriffmuir.
In maturity, Douglas grew eccentric, and perhaps insane, marrying Margaret of Mains( a fair match by some accounts); he slew Captain John Kerr( the natural son of his uncle, Lord Mark Kerr) at Douglas Castle, while the latter was guesting with him there, and was forced to flee for some time to Holland.
His residence of Douglas Castle was plundered by Highlanders during the Rising of 1745.
He fell out with his sister, Lady Jane Douglas, when he discovered her secret marriage to John Stewart of Grantully, and treated her with great cruelty.
In 1755, Douglas Castle burned, and he hired Robert Adam to rebuild it, although the work was never finished, being halted by the Duke's death.
The Duke married Margaret Douglas, daughter of James Douglas of Mains, in 1758, who succeeded in reconciling him with Archibald, his nephew by Lady Jane( who had died in 1754).
Ultimately, the Duke was persuaded to entail his estates upon Archibald, a decision which led to the celebrated Douglas Cause upon his death, when the Duke of Hamilton( who inherited the Marquessate of Douglas) and his kin unsuccessfully contested Archibald's legitimacy.

Question: Were Sonny Curtis and Archibald Douglas, 1St Duke Of Douglas of the same nationality?
Answer: no