When the British Royal Family abandoned all German titles by Letters Patent issued by King George V in June 1917 . , Prince Alexander of Teck gave up the title `` Prince of Teck '' in the Kingdom of WÃ 1\/4 rttemberg and the style Serene Highness , and took the surname Cambridge , . When the British Royal Family abandoned all Germanic titles by Letters Patent issued by King George V in June 1917 , Prince Alexander of Teck adopted the surname Cambridge , became ( briefly ) Sir Alexander Cambridge , then the Earl of Athlone , relinquishing the title `` Prince of Teck '' in the Kingdom of WÃ 1\/4 rttemberg and the style Serene Highness .