The Oath of Supremacy, originally imposed by King Henry VIII of England

Henry VIII of England

Henry VIII was King of England from 21 April 1509 until his death. He was Lord, and later King, of Ireland, as well as continuing the nominal claim by the English monarchs to the Kingdom of France...

 through the Act of Supremacy 1534, but repealed by his daughter, Queen Mary I of England

Mary I of England

Mary I was queen regnant of England and Ireland from July 1553 until her death.She was the only surviving child born of the ill-fated marriage of Henry VIII and his first wife Catherine of Aragon. Her younger half-brother, Edward VI, succeeded Henry in 1547...

 and reinstated under Mary's sister, Queen Elizabeth I of England

Elizabeth I of England

Elizabeth I was queen regnant of England and Ireland from 17 November 1558 until her death. Sometimes called The Virgin Queen, Gloriana, or Good Queen Bess, Elizabeth was the fifth and last monarch of the Tudor dynasty...

 under the Act of Supremacy 1559

Act of Supremacy 1559

The Act of Supremacy 1558 was an Act of the Parliament of England, passed under the auspices of Queen Elizabeth I of England. It replaced the original Act of Supremacy 1534 issued by Elizabeth's father, Henry VIII, which arrogated ecclesiastical authority to the monarchy, and which had been...

, provided for any person taking public or church office in England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 to swear allegiance to the monarch as Supreme Governor

Supreme Governor of the Church of England

The Supreme Governor of the Church of England is a title held by the British monarchs which signifies their titular leadership over the Church of England. Although the monarch's authority over the Church of England is not strong, the position is still very relevant to the church and is mostly...

 of the Church of England

Church of England

The Church of England is the officially established Christian church in England and the Mother Church of the worldwide Anglican Communion. The church considers itself within the tradition of Western Christianity and dates its formal establishment principally to the mission to England by St...

. Failure to do so was to be treated as treason

Treason

In law, treason is the crime that covers some of the more extreme acts against one's sovereign or nation. Historically, treason also covered the murder of specific social superiors, such as the murder of a husband by his wife. Treason against the king was known as high treason and treason against a...

able. The Oath was later extended to include Members of Parliament

Member of Parliament

A Member of Parliament is a representative of the voters to a :parliament. In many countries with bicameral parliaments, the term applies specifically to members of the lower house, as upper houses often have a different title, such as senate, and thus also have different titles for its members,...

 and people studying at universities

University

A university is an institution of higher education and research, which grants academic degrees in a variety of subjects. A university is an organisation that provides both undergraduate education and postgraduate education...

.

Text of the Oath as published in 1559:

I, A. B., do utterly testify and declare in my conscience that the Queen's Highness is the only supreme governor of this realm, and of all other her Highness's dominions and countries, as well in all spiritual or ecclesiastical things or causes, as temporal, and that no foreign prince, person, prelate, state or potentate hath or ought to have any jurisdiction, power, superiority, pre-eminence or authority ecclesiastical or spiritual within this realm; and therefore I do utterly renounce and forsake all foreign jurisdictions, powers, superiorities and authorities, and do promise that from henceforth I shall bear faith and true allegiance to the Queen's Highness, her heirs and lawful successors, and to my power shall assist and defend all jurisdictions, pre-eminences, privileges and authorities granted or belonging to the Queen's Highness, her heirs or successors, or united or annexed to the imperial crown of this realm. So help me God, and by the contents of this Book.

Roman Catholics who refused to take the Oath of Supremacy, for example Sir Thomas More

Thomas More

Sir Thomas More , also known by Catholics as Saint Thomas More, was an English lawyer, social philosopher, author, statesman and noted Renaissance humanist. He was an important councillor to Henry VIII of England and, for three years toward the end of his life, Lord Chancellor...

, were indicted for treason on charges of praemunire

Praemunire

In English history, Praemunire or Praemunire facias was a law that prohibited the assertion or maintenance of papal jurisdiction, imperial or foreign, or some other alien jurisdiction or claim of supremacy in England, against the supremacy of the Monarch...

. Such persons were generally executed.

Some of the language in the Oath would later inspire the United States Oath of Citizenship

Oath of citizenship (United States)

The United States Oath of Allegiance is an oath that must be taken by all immigrants who wish to become United States citizens...

.