Alastair Arthur Windsor, 2nd Duke of Connaught and Strathearn (9 August 1914 – 26 April 1943) was for the three first years of his life a Prince of the United Kingdom and a Prince of Saxe-Coburg and Gotha, Duke in Saxony, styled in the UK His Highness
Prince Alastair of Connaught and Strathearn, the only child of Prince Arthur of Connaught and Princess Alexandra, 2nd Duchess of Fife. He was a British royal and an heir of two Royal dukedoms from both his parents' sides, as his father was the only son and heir of The Prince Arthur, 1st Duke of Connaught (a son of Queen Victoria), and his mother was the elder daughter of The Princess Louise, Princess Royal (a daughter of King Edward VII). Princess Alexandra was also the heiress of her father, Alexander Duff, 1st Duke of Fife, and in turn, Alastair Arthur was born to be the 3rd Duke of Fife in the future.
At the time of his death in 1943, the Duke of Connaught and Strathearn was the only living male-member of the Windsor dynasty who was not descended from George V, who changed the Royal House's name in 1917 and forbade him a Royal status and title, as he was a male-line great-grandchild of a Sovereign (Victoria).
After his death, there were no other heirs to the Dukedom of Connaught and Strathearn, as he was the only male-line grandchild of The Prince Arthur, its grantee, and it became exticnt. The Dukedom of Fife, which was able to pass through the lines of its grantee's daughters, passed after the death of 2nd Duchess to Alastair Arthur's maternal first cousin, James Carnegie, the only child of Princess Maud of Fife, younger daughter the 1st Duke of Fife and Louise, the Princess Royal.
Ingrid, Queen consort of Denmark, born a Princess of Sweden, the mother of current reigning Queen Margrethe II of Denmark and Anne-Marie, former Queen consort of the Hellens, was one of Alastair Arthur's paternal first cousins. His another paternal first cousin was Prince Gustav Adolf of Sweden, the father of current reigning King Carl XVI Gustaf of Sweden.