Plots against Cardinal Beaton had begun circulating as early as 1544.

The conspirators were led by Norman Leslie, master of Rothes, and William Kirkcaldy of Grange.
The Leslies had suffered from the expansion of Beaton's interest in Fife; while Kirkcaldy's uncle, James Kirkcaldy of Grange, held Protestant sympathies and had been removed in 1543 as treasurer of the realm, through Beaton's influence.
They were joined by John Leslie of Parkhill, one of the Fife lairds angered at the murder of Wishart.
Leslie and Kirkcaldy managed to obtain admission to St Andrews Castle at daybreak of 29 May 1546, killing the porter in the process.
They then murdered the Cardinal, mutilating the corpse and hanging it from a castle window.

At the time it was widely believed that his death was in the interests of Henry VIII of England, who regarded Beaton as the chief obstacle to his policy in Scotland; the Cardinal's murder was certainly a significant point in the eventual triumph of Protestantism north of the Border.

At the time of his death, David Cardinal Beaton was Lord Chancellor of Scotland, Archbishop of St Andrews, and Cardinal Legate in Scotland.
He was succeeded as Archbishop of Saint Andrews by Dr. John Hamilton.
Plots against Cardinal Beaton had begun circulating as early as 1544.
The conspirators were led by Norman Leslie, master of Rothes, and William Kirkcaldy of Grange. The Leslies had suffered from the expansion of Beaton's interest in Fife; while Kirkcaldy's uncle, James Kirkcaldy of Grange, held Protestant sympathies and had been removed in 1543 as treasurer of the realm, through Beaton's influence. They were joined by John Leslie of Parkhill, one of the Fife lairds angered at the murder of Wishart. Leslie and Kirkcaldy managed to obtain admission to St Andrews Castle at daybreak of 29 May 1546, killing the porter in the process. They then murdered the Cardinal, mutilating the corpse and hanging it from a castle window. 
At the time it was widely believed that his death was in the interests of Henry VIII of England, who regarded Beaton as the chief obstacle to his policy in Scotland; the Cardinal's murder was certainly a significant point in the eventual triumph of Protestantism north of the Border.
At the time of his death, David Cardinal Beaton was Lord Chancellor of Scotland, Archbishop of St Andrews, and Cardinal Legate in Scotland. He was succeeded as Archbishop of Saint Andrews by Dr. John Hamilton.
David Beaton