The primary source reference for research into this field are the nine volumes of Sir Balfour Paul's work, "The Scots Peerage".
Dukes in the Peerage of Scotland
The Dukedom, the first and highest rank in the peerage, was introduced into Scotland as a peerage title by King Robert III on 28 April 1398 when he created his eldest son, David, known as "the Steward of Scotland", Duke of Rothesay. It would seem that from its creation it was, like the Dukedom of Cornwall in England, intended to be held by the Heir to the Throne. It was not until an Act of Parliament, 27 November 1469, that the Lordship of Bute, with the Castle of Rothesay and other lands, were formally settled on the first born son of the Kings of Scotland. Accordingly each such son has since that period, from either their birth or their father's succession to the Throne, been considered as Duke of Rothesay, Earl of Carrick and Baron of Renfrew as also Prince and Steward of Scotland and Lord of the Isles. The second Dukedom to be created in Scotland was also conferred on 28 April 1398 upon Robert Stewart, Earl of Fife and uncle of the Duke of Rothesay, under the title of Duke of Albany (being defined as those parts of Scotland that are north of the Firths of Clyde and Forth).
As in England, grants of the ducal style were at first strictly confined to near relatives of the King, either by blood or by marriage. The first subject to receive a dukedom who was not a member or close relation of the Royal Family was David Lindsay, 5th Earl of Crawford, who was created Duke of Montrose in 1488.
The last of the 28 Scottish Dukedoms was that of Roxburghe, created in 1707 for John Ker, 5th Earl of Roxburghe.