The Act for the Naturalization of the Most Excellent Princess Sophia, Electress and Duchess Dowager of Hanover, and the Issue of her Body was an Act of the Parliament of England (4 & 5 Ann. c. 16.) in 1705. It followed the Act of Settlement 1701 whereby Dowager Electress Sophia of Hanover and her Protestant descendants were declared to be in the line of succession to the throne (her son George I later became king).
Sophia, a granddaughter of James VI of Scotland and I of England, was not considered to be an Englishwoman as she had not been born in England. This Act naturalized her and "the issue of her body", as English subjects, providing that they were not a Catholic. Any person born to a descendant of Sophia could also claim to be the "issue of her body".
This was first tested between 1955 and 1957 when Prince Ernest Augustus of Hanover successfully claimed British nationality on this basis after considerable litigation. See the thorough discussion by A. Lyon at Statute Law Review 20:2 (1999) 174-84. In 1947 Prince Frederick of Prussia also succeeded in his claim.
The Act was repealed by section 34 of, and Part II of Schedule 4 to, the British Nationality Act 1948. However, any non-Catholic descendant of the Electress who had already been born when the repealing statute was enacted had already automatically acquired the status of a British subject, and so there are still people alive today who can claim British nationality under the Sophia Naturalization Act. That was the case of Ernest Augustus himself, who was only recognized by the courts as a British subject in 1957, years after the repeal of the Sophia Naturalization Act; because he was born and was a Protestant when the Act was still in force, the courts recognized that by that fact he had already acquired citizenship, so that the repeal of the statute did not affect his status.Also Alexander, Crown Prince of Yugoslavia was given British citizenship using the Sophia Naturalization Act.However, in the present time, most people concerned who would claim citizenship would basically only reach the status of British Overseas citizen.