Supreme Governor of the Church of England in the context of "Royal peculiar"

The archbishop of Canterbury is the senior bishop and a principal leader of the Church of England, the ceremonial head of the worldwide Anglican Communion, the bishop of the diocese of Canterbury and metropolitan of the Province of Canterbury. By virtue of their office the archbishop is also a Lord Spiritual, one of the 26 Church of England bishops who sit in the House of Lords of the Parliament of the United Kingdom. The office has been vacant since 7 January 2025 following the resignation of Justin Welby, the 105th archbishop. Dame Sarah Mullally, currently the bishop of London, will become archbishop on 28 January 2026; she will be the first woman to hold the office.

The first archbishop was Augustine of Canterbury, the "Apostle to the English", who was sent to England by Pope Gregory the Great and arrived in 597. From Augustine until William Warham the archbishops of Canterbury were in full communion with the Catholic Church. During the English Reformation, King Henry VIII broke communion with Rome and proclaimed himself the head of the Church of England. Thomas Cranmer, appointed in 1533, became the first Protestant archbishop of Canterbury and would become one of the most important figures in the development of Anglicanism.

The Scottish Episcopal Church (Scots: Scots Episcopal Kirk; Scottish Gaelic: Eaglais Easbaigeach na h-Alba) is a Christian denomination in Scotland. Scotland's third largest church, the Scottish Episcopal Church has 275 local congregations. It is also an ecclesiastical province of the Anglican Communion.

A continuation of the episcopalian "Church of Scotland" as intended by James VI, and as it was from the Restoration of Charles II to the re-establishment of Presbyterianism in Scotland following the Glorious Revolution, it recognises the archbishop of Canterbury of the Church of England as president of the Anglican Instruments of Communion, but without jurisdiction in Scotland per se. Additionally, while the British monarch holds the title of Supreme Governor of the Church of England, in Scotland the monarch maintains private links to both the Presbyterian Church of Scotland and the Scottish Episcopal Church, though in Scotland they attend and are a member (but not the leader) of the former. The church is led by a Primus, who is elected from the seven Bishops of the Scottish Episcopal Church from among their number to serve as a primus inter pares or ‘first among equals’ as the Senior Bishop. The current primus of the Scottish Episcopal Church is Mark Strange, elected in 2017.

The Crown Jewels of the United Kingdom, originally the Crown Jewels of England, are a collection of royal ceremonial objects kept in the Jewel House at the Tower of London, which include the coronation regalia and vestments worn by British monarchs.

The coronation regalia are the only working set in Europe and the collection is the most historically complete of any royal regalia in the world. Objects used at the coronation ceremony variously denote the monarch's roles as head of state of the United Kingdom, Supreme Governor of the Church of England, and head of the British armed forces. The regalia feature heraldic devices and national emblems of England, Scotland, Wales, Northern Ireland, and other Commonwealth countries.

The Oath of Supremacy required any person taking public or church office in the Kingdom of England, or in its subordinate Kingdom of Ireland, to swear allegiance to the monarch as Supreme Governor of the Church. Failure to do so was to be treated as treasonable. The Oath of Supremacy was originally imposed by King Henry VIII of England through the Act of Supremacy 1534, but repealed by his elder daughter, Queen Mary I of England, and reinstated under Henry's other daughter and Mary's half-sister, Queen Elizabeth I of England, under the Act of Supremacy 1558. The Oath was later extended to include Members of Parliament (MPs) and people studying at universities. In 1537, the Irish Supremacy Act was passed by the Parliament of Ireland, establishing Henry VIII as the supreme head of the Church of Ireland. As in England, a commensurate Oath of Supremacy was required for admission to offices.

In 1801, retained by the United Kingdom of Great Britain and Ireland, the oath continued to bar Catholics from Parliament until substantially amended by the Roman Catholic Relief Act 1829. The requirement to take the oath for Oxford University students was not removed until the Oxford University Act 1854.