Mary was born on 8 December 1542 at Linlithgow Palace, Linlithgow, Scotland, to James V, King of Scots, and his French second wife, Mary of Guise. She was said to have been born prematurely and was the only legitimate child of James to survive him.[5] She was the great-niece of King Henry VIII of England, as her paternal grandmother, Margaret Tudor, was Henry VIII's sister. On 14 December, six days after her birth, she became Queen of Scotland when her father died, perhaps from the effects of a nervous collapse following the Battle of Solway Moss,[6] or from drinking contaminated water while on campaign.[7] A popular legend, first recorded by John Knox, states that James, hearing on his deathbed that his wife had given birth to a daughter, ruefully exclaimed, "It came with a lass, it will pass with a lass!"[8] His House of Stewart had gained the throne of Scotland by the marriage of Marjorie Bruce, daughter of Robert the Bruce, to Walter Stewart, 6th High Steward of Scotland. The Crown had come to his family through a woman, and would be lost from his family through a woman. This legendary statement came true much later—not through Mary, whose son by one of her Stewart cousins became king, but through his descendant Anne, Queen of Great Britain.[9] Mary was baptised at the nearby Church of St Michael shortly after she was born.[10] Rumours spread that she was weak and frail,[11] but an English diplomat, Ralph Sadler, saw the infant at Linlithgow Palace in March 1543, unwrapped by her nurse, and wrote, "it is as goodly a child as I have seen of her age, and as like to live."[12] As Mary was an infant when she inherited the throne, Scotland was ruled by regents until she became an adult. From the outset, there were two different claims to the Regency: one from the Protestant Earl of Arran, who was next in line to the throne, and the other from Catholic Cardinal Beaton. Beaton's claim was based on a version of the late king's will that his opponents dismissed as a forgery.[13] Arran, with the support of his friends and relations, became the regent until 1554 when Mary's mother managed to remove and succeed him.[14]

Mary had briefly met her English-born first cousin Henry Stuart, Lord Darnley, in February 1561 when she was in mourning for Francis. Darnley's parents, the Earl and Countess of Lennox, who were Scottish aristocrats as well as English landowners, had sent him to France ostensibly to extend their condolences while hoping for a potential match between their son and Mary.[83] Both Mary and Darnley were grandchildren of Margaret Tudor, sister of Henry VIII of England. Darnley was also a member of the House of Stuart (or Stewart), as Mary was, but he was not a patrilineal descendant of Stewart kings, but rather of their immediate ancestors, the High Stewards of Scotland. Darnley shared a more recent Stewart lineage with the Hamilton family as a descendant of Mary Stewart, Countess of Arran, a daughter of James II of Scotland. They next met on Saturday 17 February 1565 at Wemyss Castle in Scotland,[84] after which Mary fell in love with the "long lad" (as Queen Elizabeth called him—he was over six feet tall).[85] They married at Holyrood Palace on 29 July 1565, even though both were Catholic and a papal dispensation for the marriage of first cousins had not been obtained.[86][87] English statesmen William Cecil and the Earl of Leicester had worked to obtain Darnley's licence to travel to Scotland from his home in England.[88] Although her advisors had thus brought the couple together, Elizabeth felt threatened by the marriage, because as descendants of her aunt, both Mary and Darnley were claimants to the English throne.[89] Their children would inherit an even stronger, combined claim to the English succession.[90] However, Mary's insistence on the marriage seems to have stemmed from passion rather than calculation. The English ambassador Nicholas Throckmorton stated "the saying is that surely she [Queen Mary] is bewitched",[91] adding that the marriage could only be averted "by violence".[92] The union infuriated Elizabeth, who felt the marriage should not have gone ahead without her permission, as Darnley was both her cousin and an English subject.[93] Mary's marriage to a leading Catholic precipitated Mary's half-brother, the Earl of Moray, to join with other Protestant lords, including Lords Argyll and Glencairn, in open rebellion.[94] Mary set out from Edinburgh on 26 August 1565 to confront them, and on the 30th Moray entered Edinburgh, but left soon afterward having failed to take the castle. Mary returned to Edinburgh the following month to raise more troops.[95] In what became known as the Chaseabout Raid, Mary and her forces and Moray and the rebellious lords roamed around Scotland without ever engaging in direct combat. Mary's numbers were boosted by the release and restoration to favour of Lord Huntly's son, and the return of James Hepburn, 4th Earl of Bothwell, from exile in France.[96] Unable to muster sufficient support, in October Moray left Scotland for asylum in England.[97] Mary broadened her privy council, bringing in both Catholics (Bishop of Ross John Lesley and provost of Edinburgh Simon Preston of Craigmillar) and Protestants (the new Lord Huntly, Bishop of Galloway Alexander Gordon, John Maxwell of Terregles and Sir James Balfour).[98] Before long, Darnley grew arrogant. Not content with his position as king consort, he demanded the Crown Matrimonial, which would have made him a co-sovereign of Scotland with the right to keep the Scottish throne for himself if he outlived his wife.[99] Mary refused his request, and their marriage grew strained even though they conceived by October 1565. He was jealous of her friendship with her Catholic private secretary, David Rizzio, who was rumoured to be the father of her child.[100] By March 1566, Darnley had entered into a secret conspiracy with Protestant lords, including the nobles who had rebelled against Mary in the Chaseabout Raid.[101] On 9 March, a group of the conspirators, accompanied by Darnley, murdered Rizzio in front of the pregnant Mary at a dinner party in Holyrood Palace.[102] Over the next two days, a disillusioned Darnley switched sides, and Mary received Moray at Holyrood.[103] On the night of 11–12 March, Darnley and Mary escaped from the palace, and took temporary refuge in Dunbar Castle before returning to Edinburgh on 18 March.[104] The former rebels Lords Moray, Argyll and Glencairn were restored to the council.[105]

On 11 August 1586, Mary was arrested after being implicated in the Babington Plot.[195] In a successful attempt to entrap her, Walsingham had deliberately arranged for Mary's letters to be smuggled out of Chartley. Mary was misled into thinking her letters were secure, while in reality they were deciphered and read by Walsingham.[196] From these letters it was clear that Mary had sanctioned the attempted assassination of Elizabeth.[197] She was moved to Fotheringay Castle in a four-day journey ending on 25 September, and in October was put on trial for treason under the Act for the Queen's Safety before a court of 36 noblemen,[198] including Cecil, Shrewsbury, and Walsingham.[199][200] Mary denied the charges and was spirited in her defence.[201] She told her triers, "Look to your consciences and remember that the theatre of the whole world is wider than the kingdom of England".[202] She drew attention to the fact that she was denied the opportunity to review the evidence or her papers that had been removed from her, that she was denied access to legal counsel and that as a foreign anointed queen she had never been an English subject and thus could not be convicted of treason.[203] Mary was convicted on 25 October and sentenced to death with only one commissioner, Lord Zouche, expressing any form of dissent.[204] Despite this, Elizabeth hesitated to order her execution, even in the face of pressure from the English Parliament to carry out the sentence. She was concerned that the killing of a queen set a discreditable precedent, and was fearful of the consequences, especially if, in retaliation, Mary's son James formed an alliance with the Catholic powers and invaded England.[205] Elizabeth asked Paulet, Mary's final custodian, if he would contrive a clandestine way to "shorten the life" of Mary, which he refused to do on the grounds that he would not make "a shipwreck of my conscience, or leave so great a blot on my poor posterity".[206] On 1 February 1587, Elizabeth signed the death warrant, and entrusted it to William Davison, a privy councillor.[207] On the 3rd,[208] ten members of the Privy Council of England, having been summoned by Cecil without Elizabeth's knowledge, decided to carry out the sentence at once.[209]

At Fotheringhay on the evening of 7 February 1587, Mary was told that she was to be executed the next morning.[210] She spent the last hours of her life in prayer, distributing her belongings to her household, and writing her will and a letter to the King of France.[211] The scaffold that was erected in the Great Hall was two feet high and draped in black. It was reached by two or three steps and furnished with the block, a cushion for her to kneel on and three stools, for her and the earls of Shrewsbury and Kent, who were there to witness the execution.[212] The executioners (one named Bull and his assistant) knelt before her and asked forgiveness. She replied, "I forgive you with all my heart, for now, I hope, you shall make an end of all my troubles."[213] Her servants, Jane Kennedy and Elizabeth Curle, and the executioners helped Mary to remove her outer garments, revealing a velvet petticoat, satin bodice and a pair of sleeves all in dark red, the liturgical colour of martyrdom in the Catholic Church.[214] As she disrobed she smiled and said that she "never had such grooms before ... nor ever put off her clothes before such a company".[215] She was blindfolded by Kennedy with a white veil embroidered in gold, and knelt down on the cushion in front of the block. She positioned her head on the block and stretched out her arms. Her last words were, "In manus tuas, Domine, commendo spiritum meum" ("Into thy hands, O Lord, I commend my spirit").[216] Copy of Mary's death mask in Falkland PalaceIt took two strikes to behead Mary: the first blow missed her neck and struck the back of her head. The second blow severed the neck, except for a small bit of sinew that the executioner cut through by using the axe as a saw. Afterward, the executioner held her head aloft and declared, "God save the Queen." At that moment, the auburn tresses in his hand turned out to be a wig and the head fell to the ground, revealing that Mary had had very short, grey hair.[217] A small dog owned by the queen, a Skye terrier, is said to have been hiding among her skirts, unseen by the spectators. Following the beheading, it refused to be parted from its owner's body and was covered in her blood, until it was forcibly taken away and washed.[218] Items supposedly worn or carried by Mary at her execution are of doubtful provenance;[219] contemporary accounts state that all her clothing, the block, and everything touched by her blood was burned in the fireplace of the Great Hall to obstruct relic-hunters.[218]