The Act of Settlement is an Act of the Parliament of England that was passed in 1701 to settle the succession to the English and Irish crowns and thrones on the Electress Sophia of Hanover (a granddaughter of James I) and her Protestant heirs.
The act was prompted by the failure of William and Mary, as well as of Mary’s sister Princess Anne, to produce any surviving children, and the Roman Catholic religion of nearly all other members of the House of Stuart. The line of Sophia of Hanover was the most junior among the Stuarts, but consisted of convinced Protestants. Sophia herself went to England to campaign for the act, though Queen Anne barely outlived Sophia, whose son duly became King George I and started the Hanoverian dynasty in 1714.
The act played a seminal role in the formation of the Kingdom of Great Britain. England and Scotland had shared a monarch since 1603, but had remained separately governed countries. The Scottish parliament was more reluctant than the English to abandon the House of Stuart, members of which had been Scottish monarchs long before they became English ones. English pressure on Scotland to accept the Act of Settlement led to the parliamentary union of the two countries in 1707.
Anyone who becomes a Roman Catholic, or who marries a Roman Catholic, becomes disqualified to inherit the throne under the Act of Settlement. The act also placed limits on both the role of foreigners in the British government and the power of the monarch with respect to the Parliament of England, though some of those provisions have been altered by subsequent legislation.
Along with the Bill of Rights 1689, the Act of Settlement remains today one of the main constitutional laws governing the succession not only to the throne of the United Kingdom, but also to those of the other Commonwealth realms, whether by willing deference by a realm to the act as a British statute or as a patriated part of a particular realm’s constitution. The Act of Settlement cannot be altered in any realm except by that realm’s own parliament and, by convention, only with the consent of all the other realms, as it touches on the succession to the shared crown