The title Duke of Edinburgh is linked to the capital of Scotland, and was first appointed in 1726, and but it is not a Scottish peerage as such, but a Peerage of Great Britain, and it is an appointment given to members of the British Royal Family. The title does not carry any land or properties with it and it will return to the crown if there are no descendants. It was first granted to Prince Frederick by his grandfather, King George I in 1726, when he was 19. He had actually remained in Hanover when his parents came over to England twelve years earlier.
When he died in 1751, the title together with his other titles passed to his son Prince George. When Prince George succeeded as King George III, the title merged with the crown. However, King George III decided to resurrect the title for his younger brother, Prince William Henry in 1764. He was made Duke of Edinburgh and also of Gloucester. Both these titles had been held by their father, and the feeling in doing this was to boost the cohesion between the two countries by giving him a title that reflected both countries. He also received a subsidiary title, Earl of Connaught which drew in the third country of the union. His son Prince William Frederick inherited the title upon his father’s death in 1805, but his marriage to his cousin Princess Mary, daughter of George III, remained childless and upon his death in 1834 the title returned to the crown.
The title was next given by Queen Victoria in her birthday honours in 1866 to her second son, Prince Alfred who was twenty-two at the time. He retained his English titles, when in 1893 he succeeded his paternal uncle of Duke of Saxe-Coburg and Gotha, but when he died in 1900 he had been predeceased by his only son and so the title passed back to the crown.
The current title was bestowed on Prince Philip in 1947 by King George VI, who had earlier renounced his claims to the Greek and Danish thrones when he married Princess Elizabeth, who at that time became Duchess of Edinburgh. It was announced in 1999 after his marriage that the title will eventually go to Prince Edward. This will be as a gift of the Crown, as be succession it would in theory pass to Prince Charles, and then Prince William. However, it is very sensible to re-grant the title this way, both Prince Edward and his wife, the Countess of Wessex have been deeply involved with the Duke of Edinburgh Award scheme.