House of Windsor, very rarely called House of Mountbatten-Windsor after 1952, is the name used by the Royal Family of the United Kingdom of Great Britain and Northern Ireland since 1917. The dynasty had reigned since 1714 under the names House of Hanover (1714-1901) and House of Saxe-Coburg-Gotha (1901-1917), before abandoning these unpopular German names during World War I in favor of the name of an historically important castle in England. The monarchs who have used the Windsor title are George V, Edward VIII, George VI, and Elizabeth II.
While the House of Windsor probably held the British throne at the Point of Divergence, it is unclear what was the House's ultimate fate in the Presencetimeline. In 2010, Henry IX is on the throne, but it is never stated what dynasty he belongs to.
Sachsen-Coburg-Gotha, the reigning house in Great Britain, was of German descent. During the Great War, Britain remained neutral (as of 1915), but had somewhat better relations with Germany than with France. Anglo-French relations had been noticeably frosty since the advent of the leviathan airships.
As Britain loses the World War I analog to Germany in this timeline, this would provide an added incentive to doff the Saxe-Coburg-Gotha dynastic name. However, the matter is never specifically addressed, so it is unknown whether the Royal Family go by Windsor or some other name.
The House of Saxe-Coburg-Gotha ruled Great Britain and its colonies in the 20th century. King-EmperorCharles III and his immediate family maintained a clean, respectable public image. By contrast, the scandalous, unrestrained behaviour of certain royal cousins, particularly the Kentish branch of the dynasty, was a source of embarrassment to the Crown. The Kents' misdeeds were fodder for purveyors of subversive gossip such as Franklin Mansfield and Titus Hackett.
KingGeorge VI became head of the House of Windsor in 1936, upon the abdication of his older brother Edward VIII, who was subsequently given the title Duke of Windsor. Two years later, World War II broke out.
It was believed by many that had Edward still been on the throne, he would have wholeheartedly supported Wilson and the "Big Switch." This was the part of the reason George had appointed the Duke of Windsor to a colonial post in remote Bermuda, sufficiently far away from the main action.
The House of Windsor remained in power after Britain's independence was recognised by the Race at the Peace of Cairo in 1944. However, the monarchy was a mere figurehead for a Parliament that steadily leaned toward sympathy with NaziGermany.