The title was first created in the Peerage of Great Britain on 26 July 1726 by King George I, who bestowed it on his grandson Prince Frederick, who also became Prince of Wales the following year. The subsidiary titles of the dukedom were Baron of Snowdon, in the County of Caernarvon, Viscount of Launceston, in the County of Cornwall, Earl of Eltham, in the County of Kent, and Marquess of the Isle of Ely. These titles were also in the Peerage of Great Britain. The marquessate was apparently erroneously gazetted as Marquess of the Isle of Wight although Marquess of the Isle of Ely was the intended title. In later editions of the London Gazette the Duke is referred to as the Marquess of the Isle of Ely. Upon Frederick's death, the titles were inherited by his son Prince George. When Prince George became King George III in 1760, the titles "merged into the Crown", and ceased to exist.
1866 creation
re-created the title, this time in the Peerage of the United Kingdom, on 24 May 1866 for her second son Prince Alfred, instead of Duke of York, the traditional title of the second son of the Monarch. The subsidiary titles of the dukedom were Earl of Kent and Earl of Ulster, also in the Peerage of the United Kingdom. When Alfred became the Duke of Saxe-Coburg and Gotha in 1893, he retained his British titles. His only son Alfred, Hereditary Prince of Saxe-Coburg and Gotha committed suicide in 1899, so the Dukedom of Edinburgh and subsidiary titles became extinct upon the elder Alfred's death in 1900.
1947 creation
The title was created for a third time on 19 November 1947 by King George VI, who bestowed it on his son-in-law Philip Mountbatten, when he married Princess Elizabeth. Subsequently, Elizabeth was styled "HRH The Princess Elizabeth, Duchess of Edinburgh" until her accession in 1952. The subsidiary titles of the dukedom are Earl of Merioneth and Baron Greenwich, of Greenwich in the County of London. Like the dukedom, these titles are also in the Peerage of the United Kingdom. Earlier that year, Philip had renounced his Greek and Danish royal titles along with his rights to the Greek throne. In 1957, Philip became a Prince of the United Kingdom.
Dukes of Edinburgh
First creation, 1726
Second creation, 1866
Third creation, 1947
Possible future creations
It was announced in 1999, at the time of the wedding of Prince Edward, Earl of Wessex, that he would follow his father as Duke of Edinburgh. This is unlikely to happen by direct inheritance, as Prince Edward is the youngest of Prince Philip's three sons. Rather, the title is expected to be newly created for Prince Edward after it "eventually reverts to the crown" after "both the death of the current Duke of Edinburgh and the Prince of Wales' succession as King."
Line of succession
Although the following individuals are in the line of succession to the Dukedom, they are also in line of succession to the throne. As a consequence, should one of the following individuals become king while Duke, the Dukedom of Edinburgh would cease to exist, as it would merge with the Crown.