The Act of Supremacy was passed by the English Parliament in a historical move that proclaimed King Henry VIII as the Supreme Head of the Church of England. This act effectively terminated the influence of the Pope and the Roman Catholic Church in England, transforming the religious landscape of the country. The origins of this monumental action lay in Henry's personal life; he sought to annul his marriage to Catherine of Aragon to marry Anne Boleyn. However, the Pope, under pressure from Catherine’s nephew, the Holy Roman Emperor Charles V, refused Henry's request, leading to the belief that the Pope's authority over English matters was untenable.

The new Act of Supremacy was a bold declaration of independence from Rome that resonated throughout England. By establishing the monarch as the ultimate religious authority, it enabled Henry and his successors to dictate ecclesiastical policies, control church appointments, and seize church properties. The act was not just a localized religious reform; it precipitated the English Reformation, a broader movement that saw the establishment of Protestantism and significant changes in religious practices and beliefs across Europe. This reformed church not only reflected Henry's personal interests but also laid the foundations for vast socio-political changes within England.

Over time, the Act of Supremacy faced resistance from various factions, notably from Catholic loyalists who viewed it as heretical. The execution of key figures, like Sir Thomas More, who opposed the Act, highlighted the tensions of the era. Within a few years, England would see new religious laws and significant shifts in power dynamics between church and state, leading to a period of religious turmoil and violence.