The Southampton Plot: Execution of Richard, earl of Cambridge took place on 5th August 1415.
The Southampton Plot was a conspiracy to depose King Henry V and replace him with Edward Mortimer, 5th Earl of March. It was the Earl of March himself who revealed the plot to the king, which resulted in the swift arrest of those involved at mustering points around Southampton. It culminated in trials and the execution by beheading of those behind the Southampton Plot. Richard, earl of Cambridge was executed outside the Bargate on 5th August 1415.
The plot is recorded in several sources, the following is from Thomas Walsingham’s Chronica Majora:
“Lord Henry [Scrope] was joined in his treason by Richard, earl of Cambridge, brother of the duke of York, and by Thomas Grey, a knight of the north. In fact it was the king who had made Richard an earl, enriching him with many goods and so honouring him by sitting next to him in parliament and other public places that he raised him above his other companions because of his birth and family. But no kindness shown, no benefit bestowed was able to prevent the traitors from taking up arms together to kill their great benefactor. So when they had put the finishing touches to their wicked plot, they approached the earl of March with winning words and said they had formed a plan by which his own honour would necessarily be immensely increased, if only he could agree to their designs and confirm by taking a corporal oath that he would in no way reveal their plan. When he had done this, they said that they would suddenly kill the king with their swords and at once take the earl himself and elevate him to the throne of England. The young man shuddered with horrow when he heard this, but on that occasion did not dare to oppose them or to say anything. But as soon as he could, when a suitable hour arrived, he went to the king and revealed to him the plot of these wicked men.”
The plot shows that the Lancastrian kings still faced opposition some 16 years after Henry Bolingbroke had overthrown Richard II. That the plot aimed to put the Earl of March on the throne is telling: it was the Mortimer family who had been heirs to Richard II.
The Earl of March revealing the plot to King Henry V implicated his own brother-in-law, Richard, earl of Cambridge.
Execution of Richard of Conisborough, earl of Cambridge
The earl was beheaded at Southampton on 5th August 1415, less than a week before Henry Vs army set sail for France. The earl’s son was a minor at the time. Before reaching his majority he stood to inherit the Duchy of York through the loss in battle of his uncle on his father’s side and, perhaps ironically, the earldom of March.