Final answer:
The Act of Supremacy, passed in 1559, separated the Church of England from the Roman Catholic Church and established the monarch as the Supreme Head of the Church.
Step-by-step explanation:
The Act of Supremacy was a significant piece of legislation passed by the English Parliament in 1559. It declared the Church of England as separate from the Roman Catholic Church and reinstated the Book of Common Prayer as the only legal form of worship in England. The Act of Supremacy solidified England's break from Catholicism and established the monarch as the Supreme Head of the Church of England.