Philip II (21 May 1527 13 September 1598), also known as Philip the Prudent (Spanish: Felipe el Prudente), was King of Spain from 1556, King of Portugal from 1580, and King of Naples and Sicily from 1554 until his death in 1598. He was also jure uxoris King of England and Ireland from his marriage to Queen Mary I in 1554 until her death in 1558. He was also Duke of Milan from 1540. From 1555, he was Lord of the Seventeen Provinces of the Netherlands.

The son of Emperor Charles V and Isabella of Portugal, Philip inherited his father's Spanish Empire in 1556 and succeeded to the Portuguese throne in 1580 following a dynastic crisis. The Spanish conquest of the Inca Empire and of the Philippines, named in his honor by Ruy Lpez de Villalobos, were completed during his reign. Under Philip II, Spain reached the height of its influence and power, sometimes called the Spanish Golden Age, and ruled territories in every continent then known to Europeans. Philip led a highly debt-leveraged regime, seeing state defaults in 1557, 1560, 1569, 1575, and 1596. This policy was partly the cause of the declaration of independence that created the Dutch Republic in 1581. Philip finished building the royal palace El Escorial in 1584.

Deeply devout, Philip saw himself as the defender of Catholic Europe against the Ottoman Empire and the Protestant Reformation. In 1584, Philip signed the Treaty of Joinville funding the French Catholic League over the following decade in its civil war against the French Huguenots. In 1588, he sent an armada to invade Protestant England, with the strategic aim of overthrowing Elizabeth I and re-establishing Catholicism there, but his fleet was defeated in a skirmish at Gravelines (northern France) and then destroyed by storms as it circled the British Isles to return to Spain. The following year Philip's naval power was able to recover after the failed invasion of the English Armada into Spain. Two more Spanish armadas unsuccessfully tried to invade England in 1596 and 1597. The Anglo-Spanish war carried on until 1604, six years after Philip's death.Under Philip, an average of about 9,000 soldiers were recruited from Spain each year, rising to as many as 20,000 in crisis years. Between 1567 and 1574, nearly 43,000 men left Spain to fight in Italy and the Low Countries (modern-day Belgium, Luxembourg, and the Netherlands).Philip was described by the Venetian ambassador Paolo Fagolo in 1563 as "slight of stature and round-faced, with pale blue eyes, somewhat prominent lip, and pink skin, but his overall appearance is very attractive. ... He dresses very tastefully, and everything that he does is courteous and gracious." Philip was married four times; all his wives predeceased him.

Mary, Queen of Scots (8 December 1542 – 8 February 1587), also known as Mary Stuart or Mary I of Scotland, was Queen of Scotland from 14 December 1542 until her forced abdication in 1567.

The only surviving legitimate child of James V of Scotland, Mary was six days old when her father died and she acceded to the throne. During her childhood, Scotland was governed by regents, first by the heir to the throne, James Hamilton, Earl of Arran, and then by her mother, Mary of Guise. In 1548, she was betrothed to Francis, the Dauphin of France, and was sent to be brought up in France, where she would be safe from invading English forces during the Rough Wooing. Mary married Francis in 1558, becoming queen consort of France from his accession in 1559 until his death in December 1560. Widowed, Mary returned to Scotland in August 1561. Following the Scottish Reformation, the tense religious and political climate that Mary encountered on her return to Scotland was further agitated by prominent Scots such as John Knox, who openly questioned whether her subjects had a duty to obey her. The early years of her personal rule were marked by pragmatism, tolerance, and moderation. She issued a proclamation accepting the religious settlement in Scotland as she had found it upon her return, retained advisers such as James Stewart, Earl of Moray, and William Maitland of Lethington, and governed as the Catholic monarch of a Protestant kingdom.

Mary married her half-cousin, Henry Stuart, Lord Darnley, in 1565, and in June 1566, they had a son, James. In February 1567, Darnley's residence was destroyed by an explosion, and he was found murdered in the garden. James Hepburn, 4th Earl of Bothwell, was generally believed to have orchestrated Darnley's death, but he was acquitted of the charge in April 1567, and the following month, he married Mary. Following an uprising against the couple, Mary was imprisoned in Loch Leven Castle. On 24 July 1567, she was forced to abdicate in favour of her one-year-old son. After an unsuccessful attempt to regain the throne, she fled southward seeking the protection of her first cousin once removed, Elizabeth I of England. (Elizabeth was the granddaughter of Henry VII of England, and Mary was his great-granddaughter.)

Mary had once claimed Elizabeth's throne as her own and was considered the legitimate sovereign of England by many English Catholics, including participants in a rebellion known as the Rising of the North. Perceiving Mary as a threat, Elizabeth had her confined in various castles and manor houses in the interior of England. After eighteen and a half years in captivity, Mary was found guilty of plotting to assassinate Elizabeth in 1586 and was beheaded the following year at Fotheringhay Castle. Mary's life, marriages, lineage, alleged involvement in plots against Elizabeth, and subsequent execution established her as a divisive and highly romanticised historical character, depicted in culture for centuries.