The Babington Plot was a plot in 1586 to assassinate Queen Elizabeth, a Protestant, and put the rescued Mary, Queen of Scots, her Roman Catholic cousin, on the English throne. It led to the execution of Queen Mary Stuart of Scotland as a direct result of a letter sent by Mary (who had been imprisoned for 18 years since 1568 in England at the behest of Elizabeth) in which she consented directly to the assassination of Elizabeth.