The House of Windsor, previously called the House of Saxe-Coburg-Gotha (Sachsen-Coburg-Gotha), is the Royal House of the United Kingdom of Great Britain and Northern Ireland. The House was renamed Windsor on July 17, 1917 by King George V during World War I, on account of the German origins of the name, given that what was then United Kingdom of Great Britain and Ireland was at war with Germany.
Some descendants of Queen Elizabeth II and her husband, Prince Philip, Duke of Edinburgh have the surname of Mountbatten-Windsor (through an Order-in-Council given in 1960). See also: British Royal FamilyUnited Kingdom of Great Britain and Northern Ireland and other Commonwealth Realms:
Notes King George V's reign began in 1910 under the House of Saxe-Coburg-Gotha.
 Though the Irish Free State left the United Kingdom in 1922, the actual name of the kingdom was not changed until 1927. From 1927, the monarch also became the king or queen of many Commonwealth Realms, including Ireland, Australia, Canada, New Zealand, Union of South Africa, etc. Prevously they had been monarchs in not of those states, through a shared Crown of the British Empire. After 1927, it became a shared monarch wearing multiple crowns.