Anne de Mortimer - The Southampton Plot

The Southampton Plot

In 1415 Cambridge conspired with Henry Scrope, 3rd Baron Scrope of Masham, and Sir Thomas Grey (to whose son, Thomas, he had betrothed his young daughter, Isabel), to depose King Henry, and place his late wife Anne's brother, Edmund Mortimer, 5th Earl of March, on the throne. Mortimer revealed the plot to the King, and was on the commission which condemned Cambridge to death. Although Cambridge pleaded with the King for clemency, he was beheaded on 5 August 1415 and buried in the chapel of God's House at Southampton. The fleet set sail for France a few days later on 11 August 1415.

Although Cambridge's title was forfeited, he was not attainted, and his and Anne Mortimer's four-year-old son, Richard, was his heir. Within three months Cambridge's elder brother, Edward of Norwich, 2nd Duke of York, was slain at Agincourt, and Cambridge and Anne's four-year-old son was eventually heir to his uncle's titles and estates as well.

In the parliament of 1461 King Edward IV annulled the sentence which had been passed on his grandfather, Richard, Earl of Cambridge.