In 1587, Queen Elizabeth I of England reluctantly signed an unusual death warrant. Indeed, the document authorized the execution of the queens fellow monarch and cousin (once removed), Mary, Queen of Scots. Marys execution was the climax of a decades-long political conflict between the two queens. After fleeing Scotland in 1568, Mary sought refuge in England, where she became the focal point of several Catholic plots aiming to overthrow Queen Elizabeth and replace her with a Catholic monarch. Lets look into the rivalry between Queen Elizabeth and Mary, Queen of Scots, in a divided 16th-century England.Setting the Stage: Queen Elizabeth & 16th-Century EnglandPortrait of Queen Elizabeth I, by anonymous, c. 1575. Source: Wikimedia Commons/National Portrait Gallery, LondonWhen Elizabeth I ascended to the throne in 1558, her coronation was met with widespread jubilation. Her predecessor, Mary I, Elizabeths half sister, had become largely unpopular during her last years of reign, when her fierce persecution of Protestants had earned her the nickname Bloody Mary.The daughter of Henry VIII and Catherine of Aragon, Mary sought to restore Roman Catholicism in England after her father, faced with the popes refusal to grant him a divorce, had broken ties with the Church of Rome, an act that marked the beginning of the English Reformation. To pursue her re-Catholicization program, Mary wed Philip II of Spain, a decision that proved unwise, as many distrusted the Spanish monarch. In the last three years of her reign, the ruthless persecution of Protestantsabout 300 were burned at the stakehad created a tense atmosphere in the kingdom.Elizabeth I when a Princess, attributed to William Scrots, c. 1546-47. Source: Wikimedia Commons/Royal CollectionDuring her half sisters reign, Elizabeths life was often in danger. In 1154, when a Protestant rebellion tried and failed to overthrow Mary, she was imprisoned in the Tower of London. Only her poise and circumspection prevented her from meeting the same fate as her mother, Anne Boleyn.Upon her ascension to the throne, Elizabeth I pursued an opposite religious policy, restoring Protestantism in England. In 1559, the Act of Supremacy reasserted Henry VIIIs refusal to accept the idea of papal supremacy, confirming the monarch as the head of the English Church. Meanwhile, the Act of Uniformity ensured doctrinal conformity, establishing an official liturgy and requiring priests and state officials to swear an oath to the queens supremacy. Additionally, all those who did not attend Sunday services at their church would receive a fine.Queen Elizabeths religious settlement, however, did not put an end to the division lacerating the kingdom. While militant Protestants called for more drastic reforms, English Catholics also threatened the queens authority.Who Was Mary, Queen of Scots?Mary, Queen of Scots, by Franois Clouet, c. 1558-60. Source: Wikimedia Commons/Royal CollectionIn the late 1560s, the Catholic opposition to Elizabeth Is rule turned increasingly threatening. By then, the focus of the Catholic plans to overthrow Elizabeth was Mary, Queen of Scots. The only child of James V of Scotland and Mary of Guise, a French noblewoman, Mary inherited the Scottish throne when she was only six days old in 1542.Her grandmother, Margaret Tudor, was one of Henry VIIIs sisters, making Mary next in line for the English throne when it became clear Queen Elizabeth did not intend to marry. In the 1560s, many English Catholics saw her as the lawful English queen, looking upon Elizabeth as the illegitimate daughter of Anne Boleyn. Marys claim to the English crown was also backed by her father-in-law, the king of France.After spending her childhood years at the French court, Mary returned to Scotland in 1560. The previous year, the premature death of her husband, the French king Francis II, had left her a widow at the age of 18. The young queen was largely unfamiliar with the political landscape in Scotland, a country she had left at a very young age. To make matters worse, Mary followed the Roman Catholic faith, while Scotland had adopted Protestantism as the state religion.An Unwelcome GuestEmbroidered panel, depicting a ginger cat, made by Mary, Queen of Scots, during her time in captivity in England, c. 1569-84. Source: Wikimedia Commons/Royal CollectionWhile Mary initially seemed to be able to navigate the complex political landscape of Scotland, a series of unwise decisions ultimately led to her downfall. Marys troubles began in 1565, when she married Henry Stewart (Stuart), earl of Darnley. Since the beginning, the marriage was tumultuous. In 1566, Darnley even had Marys secretary, David Rizzio, murdered before her eyes. The following year, Darnley died in suspicious circumstances.Three months after her husbands death, Mary, Queen of Scots, married James Hepburn, 4th Earl of Bothwell, the chief suspect in Darnleys murder. The decision angered the Scottish nobles, who rebelled against Mary. In June 1567, she was forced to abdicate in favor of James, her one-year-old son. The following year, after her supporters suffered a defeat at the Battle of Langside, Mary was put under armed guard. She then decided to reach out to her cousin, Queen Elizabeth, asking for refuge and assistance in regaining her crown.In her first letters to Elizabeth, Mary expressed the confidence I have in you, not only for the safety of my life, but also to aid and assist me in my just quarrel. However, the deposed Scottish queen became increasingly aware she was far from a welcome guest in England. Indeed, Elizabeth, who never met her cousin face-to-face, saw Marys presence at her court as a threat to her rule. For the next 18 years of her life, Mary lived as a captive in England, closely watched by Elizabeths men.Challenging Queen Elizabeths Authority: Plots & RebellionsPortrait of Sir Francis Walsingham, Queen Elizabeths spymaster, by John de Critz, c. 1589. Source: Wikimedia Commons/National Portrait Gallery, LondonQueen Elizabeths suspicions about Mary were not unfounded. In 1569, the Earls of Westmoreland and Northumberland led the so-called Northern Rising (or Rising of the Northern Earls). During the short-lived uprising, the Catholic rebels marched south, destroying every symbol of Protestantism they encountered.Although the uprising was forcefully suppressed, the armed rebellion posed a clear challenge to Elizabeths authority and legitimacy. To make matters worse, in 1570, Pope Pius V excommunicated the English queen, declaring her an usurper. The following year, Elizabeths spy network uncovered an internal plot with foreign backing.Portrait of King Philip II of Spain, by Sofonisba Anguissola, 1565. Philip II was involved in several plots against Queen Elizabeth. Source: Wikimedia Commons/Museo del Prado, MadridKnown as the Ridolfi Plot, from its mastermind, the Florentine businessman Roberto Ridolfi, the conspiracy involved a Spanish invasion of England and the removal of Queen Elizabeth from the throne. To ensure the success of his co-conspirators plan, Ridolfi had even reached out to Philip II of Spain, Pope Pius V, and the Duke of Alba, the Spanish governor of the Netherlands. As Mary was the focal point of both attempts to remove Elizabeth from power, it became clear that her presence in England posed a serious problem.Meanwhile, news of the increasing tensions between Protestants and Catholics on the Continent heightened the already tense atmosphere of political intrigue and religious violence in England. In 1572, suspicions against the Catholics rose as news of the St. Bartholomews Day massacre of French Protestants (Huguenots) reached the English shores.In 1579, the Protestant provinces of the Low Countries, determined to strengthen their resistance against Spanish rule, formed the Union of Utrecht. In 1585, under increasing pressure to become involved in the struggle in the Netherlands, Elizabeth sent an expeditionary force to aid the Protestants in their war against Spain.The Babington PlotA contemporary copy of the Gallos Letter sent by Mary to Anthony Babington in 1586. Source: British Library/The National ArchivesAs the threats against Elizabeths life continued, the members of the Privy Council pledged to prosecute not only the direct conspirators, but also the candidate to the throne they supported. Known as the Bond of Association, this move was clearly aimed against Mary, Queen of Scots, who found herselfwilling or otherwiseinvolved in most conspiracies against Elizabeth.While closely guarded by the queens most loyal supporters, Mary sent thousands of letters to government officials, ambassadors, monarchs, and Catholic conspirators. Employing a combination of ciphers and codes to elude detection, the missives had one thing in common: securing her freedom and finding backing for her claim to the throne.Signed confession of Anthony Babington bearing his acknowledgment of the ciphers used with Mary, Queen of Scots. Source: British Library/The National ArchivesIn 1583, after Sir Francis Walsingham, Elizabeths legendary spymaster, uncovered Marys involvement in yet another Catholic plot, Mary, confined at Tutbury Castle in Staffordshire, was put under the watchful eye of Sir Amias Paulet. Fearing her life might be in danger, the Scottish queen became embroiled in the Babington Plot. The conspirators aimed to murder Elizabeth and seize power with the military assistance of Philip II, who would invade England with his forces. Philip IIs plans to conquer the island nation came to naught in 1588, when the English defeated his Invincible Armada.As she began corresponding with Anthony Babington, however, her letters were intercepted by Sir Francis Walsingham, who had learned of the conspiracy from one of his double agents. As Walsinghams network opened and deciphered the letters between Mary and Babington, cryptographer Thomas Phelippes eventually decoded a letter that would seal Marys fate. Known as the Gallows Letter, from Phelippes drawing of a gallows on its address leaf, the July 17, 1586 missive included a sentence revealing Marys agreement to Elizabeths murder: Sett the six gentlemen to woork.Mary, Queen of Scots ExecutionThe trial of Mary, Queen of Scots, in a contemporary drawing, 1586. Source: Wikimedia Commons/British LibraryArrested by Sir Francis Walsingham on August 4, Babington revealed the names of the other conspirators, probably under torture. After attempting to flee the country, he was condemned to death for high treason. Meanwhile, Marys secretaries confessed to writing the Gallows Letter at her command. Marys complicity in the plot was thus proven beyond all reasonable doubt.Queen Elizabeth was initially reluctant to sign Marys death warrant. After all, Mary was a sovereign queen of a foreign country, and Elizabeth feared that her execution might provoke the anger of Scotland and France. In the end, it was William Cecil, Lord Burghley, Elizabeths chief minister, who issued the signed warrant without the queens knowledge.Reproduction of the tomb of Mary, Queen of Scots at the National Museum of Scotland, photograph by Kim Traynor. The original, erected by James I, is in Westminster Abbey. Source: Wikimedia CommonsMary, Queen of Scots, was executed on February 8, 1587, at Fotheringhay Castle near Peterborough. When Elizabeth died without an heir in 1603, she was succeeded by Marys son, James VI of Scotland, who became the first Stuart monarch as James I of England. Like Banquo in Shakespeares Macbeth, destined not to be king himself but father of kings, Mary did, in a sense, achieve her aspiration in the end through her son.