James Boswell (1740-1795) family tree

John became the Commendator of Dryburgh Abbey in 1547 and succeeded his father as the 6th Lord Erskine in 1552. He aligned himself with the religious reformers in 1559, though he was not deeply committed to the cause. He did, however, sign a letter in 1557 inviting the Calvinist reformer John Knox back to Scotland. During the conflict between the regent, Mary of Guise, and the Lords of the Congregation, he held control of Edinburgh Castle and aimed to foster peace.

When Mary, Queen of Scots, returned to Scotland in 1561, Lord Erskine was part of her council and supported her marriage to Henry Stuart, Lord Darnley. His wife, Annabella Murray, was the daughter of William Murray of Tullibardine and a close companion of Queen Mary, earning the critique of John Knox as a "verray Jesabell."

In 1565, Erskine was awarded the earldom of Mar, restoring the title to him and his descendants; this title had previously been held by Mary's half-brother James Stewart. John Erskine is considered the 18th earl in the first creation of the title and the 1st earl in the seventh creation, though some sources vary in numbering him as the 17th or the 6th Earl.

Mar was appointed Sheriff of Stirlingshire and Keeper of Stirling Castle, including the Raploch and Gallowhill parks, on 18 July 1566. On 19 March 1567, he became the custodian of Queen Mary's son, James, at Stirling Castle, playing a crucial role in protecting the prince from Lord Bothwell. Mar was among the leaders who opposed Mary and Bothwell, contributing to the governance of Scotland after Mary was detained and abdicated at Lochleven Castle. Regent Moray tasked him with repairing Stirling Castle's fore-entry in December 1568. Following Mary's escape from Lochleven on 5 May 1568, Mar was ordered by Regent Moray to bolster security at Stirling Castle by reducing the number of castle retainers.

On 5 September 1571, he became the Regent of Scotland, but his authority was diminished by James Douglas, 4th Earl of Morton. One of Mar's initial decisions was to execute George Bell and George Calder using the wheel, a method inspired by French practices. Bell, who had aided the Queen's forces in attacking Stirling, and Calder, believed to have killed Regent Lennox, were both executed. Bell admitted under torture to inciting an attack on the Regent.

During the Marian Civil War, Mar led efforts to besiege Edinburgh and its castle, which was under William Kirkcaldy of Grange's control for Queen Mary. He positioned artillery around the city, sourced from various castles, targeting initially Adam Fullerton's house and then the city walls, although the siege was ultimately abandoned, and he sought military aid from England, following Morton's recommendation.

The King's supporters faced setbacks, including defeats in Aberdeen and the loss of Broughty Castle. Plans for Lord Maxwell's marriage were disrupted by an ambush on the party delivering supplies for the celebration. Queen Elizabeth sent ambassadors, Thomas Randolph and Henry Carey, to negotiate with Mar and the Laird of Grange, respectively.

Mar communicated with William Cecil and William Drury in England, notably through Nicolas Elphinstone. On 1 August 1572, he announced a two-month truce with the Queen's supporters. He informed Margaret Douglas, Countess of Lennox, about the truce and other matters, including the operation of a mint in Edinburgh Castle by his adversaries and the sale of one of Mary, Queen of Scots' jewels in France. In his correspondence with Cecil, Mar expressed hope for resolving border issues during the truce. Queen Elizabeth congratulated him on his regency and urged him to act against those involved in Regent Lennox's murder.

He passed away in Stirling on 29 October 1572 after a brief illness, generally believed to have been from natural causes. Nonetheless, there are suggestions that he might have been poisoned, potentially on orders from the Earl of Morton. This speculation arises from an account by James Melville, who noted Mar's sickness followed a feast hosted by Morton at Dalkeith Palace. James VI maintained a fond relationship with Mar's widow, Annabella Murray, affectionately referring to her as "Minnie." She served as the governess for his son, Prince Henry, at Stirling.