Edward VI (12 October 1537 6 July 1553) was King of England and Ireland from 28 January 1547 until his death in 1553. He was crowned on 20 February 1547 at the age of nine. Edward was the son of Henry VIII and Jane Seymour and the first English monarch to be raised as a Protestant. During his reign, the realm was governed by a regency council because he never reached maturity. The council was first led by his uncle Edward Seymour, 1st Duke of Somerset (15471549), and then by John Dudley, 1st Earl of Warwick (15501553), who from 1551 was Duke of Northumberland.

Edward's reign was marked by economic problems and social unrest that in 1549 erupted into riot and rebellion. An expensive war with Scotland, at first successful, ended with military withdrawal from Scotland and Boulogne-sur-Mer in exchange for peace. The transformation of the Church of England into a recognisably Protestant body also occurred under Edward, who took great interest in religious matters. His father, Henry VIII, had severed the link between the Church and Rome, but had never permitted the renunciation of Catholic doctrine or ceremony. It was during Edward's reign that Protestantism was established for the first time in England with reforms that included the abolition of clerical celibacy and the Mass, and the imposition of compulsory services in English.

In February 1553, at age 15, Edward fell ill. When his sickness was discovered to be terminal, he and his council drew up a "Devise for the Succession" to prevent the country's return to Catholicism. Edward named his first cousin once removed, Lady Jane Grey, as his heir, excluding his half-sisters, Mary and Elizabeth. This decision was disputed following Edward's death, and Jane was deposed by Mary nine days after becoming queen. Mary, a Catholic, reversed Edward's Protestant reforms during her reign, but Elizabeth restored them in 1559.

Henry VIII (28 June 1491 – 28 January 1547) was King of England from 22 April 1509 until his death in 1547. Henry is best known for his six marriages, and for his efforts to have his first marriage (to Catherine of Aragon) annulled. His disagreement with Pope Clement VII about such an annulment led Henry to initiate the English Reformation, separating the Church of England from papal authority. He appointed himself Supreme Head of the Church of England and dissolved convents and monasteries, for which he was excommunicated. Henry is also known as "the father of the Royal Navy," as he invested heavily in the navy, increasing its size from a few to more than 50 ships, and established the Navy Board.Domestically, Henry is known for his radical changes to the English Constitution, ushering in the theory of the divine right of kings in opposition to Papal supremacy. He also greatly expanded royal power during his reign. He frequently used charges of treason and heresy to quell dissent, and those accused were often executed without a formal trial by means of bills of attainder. He achieved many of his political aims through the work of his chief ministers, some of whom were banished or executed when they fell out of his favour. Thomas Wolsey, Thomas More, Thomas Cromwell, Richard Rich, and Thomas Cranmer all figured prominently in his administration.

Henry was an extravagant spender, using the proceeds from the dissolution of the monasteries and acts of the Reformation Parliament. He also converted the money that was formerly paid to Rome into royal revenue. Despite the money from these sources, he was continually on the verge of financial ruin due to his personal extravagance, as well as his numerous costly and largely unsuccessful wars, particularly with King Francis I of France, Holy Roman Emperor Charles V, King James V of Scotland and the Scottish regency under the Earl of Arran and Mary of Guise. At home, he oversaw the legal union of England and Wales with the Laws in Wales Acts 1535 and 1542, and he was the first English monarch to rule as King of Ireland following the Crown of Ireland Act 1542.

Henry's contemporaries considered him to be an attractive, educated, and accomplished king. He has been described as "one of the most charismatic rulers to sit on the English throne" and his reign has been described as the "most important" in English history. He was an author and composer. As he aged, he became severely overweight and his health suffered. He is frequently characterised in his later life as a lustful, egotistical, paranoid and tyrannical monarch. He was succeeded by his son Edward VI.