The first Act of Supremacy was passed on 3 November 1534 (26 Hen. VIII c. 1) by the Parliament of England. It granted King Henry VIII of England and subsequent monarchs Royal Supremacy, such that he was declared the supreme head of the Church of England. Royal Supremacy is specifically used to describe the legal sovereignty of the civil laws over the laws of the Church in England.
The act declared that the king was "the only supreme head on Earth of the Church of England" and that the English crown shall enjoy "all honours, dignities, preeminences, jurisdictions, privileges, authorities, immunities, profits, and commodities to the said dignity." The wording of the act made clear that Parliament was not granting the king the title (thereby suggesting that they had the right to withdraw it later); rather, it was acknowledging an established fact. In the Act of Supremacy, Henry abandoned Rome completely. He thereby asserted the independence of the Ecclesia Anglicana. He appointed himself and his successors as the supreme rulers of the English church. Henry had been declared "Defender of the Faith" (Fidei Defensor) in 1521 by Pope Leo X for his pamphlet accusing Martin Luther of heresy. Parliament later conferred this title upon Henry in 1544.
The 1534 Act marks the beginning of the English Reformation. There were a number of reasons for this Act, primarily the need for a male heir to the throne. Henry tried for years to obtain an annulment of his marriage to Catherine of Aragon, and had convinced himself that God was punishing him for marrying his brother's widow. Pope Clement VII refused to grant the annulment because, according to Roman Catholic teaching, a validly contracted marriage is indivisible until death, and thus the pope cannot annul a marriage simply because of a canonical impediment previously dispensed. The Treasons Act was later passed: it provided that to disavow the Act of Supremacy and to deprive the King of his "dignity, title, or name" was to be considered treason. The most famous public figure to resist the Treason Act was Sir Thomas More.
Henry's Act of Supremacy was repealed in 1554 in the reign of his staunchly Roman Catholic daughter, Queen Mary I. It was reinstated by Mary's Protestant half-sister, Queen Elizabeth I, when she ascended the throne. Elizabeth declared herself Supreme Governor of the Church of England, and instituted an Oath of Supremacy, requiring anyone taking public or church office to swear allegiance to the monarch as head of the Church and state. Anyone refusing to take the oath could be charged with treason. The use of the term Supreme Governor as opposed to Supreme Head pacified some Roman Catholics and those Protestants concerned about a female leader of the Church of England. Elizabeth, who was a politique, did not prosecute layman nonconformists, or those who did not follow the established rules of the Church of England unless their actions directly undermined the authority of the English monarch, as was the case in the vestments controversy. Thus, it was through the Second Act of Supremacy that Elizabeth I officially established the now reformed Church of England.