That the chief contriver of the deed was James Hepburn, Earl of Bothwell, is not doubted. Bothwell was brought to a mock trial and acquitted. Mary married him on May 15, just three months after her husband's murder. The question whether Mary herself shared in the crime has remained one of the most interesting of historical problems.
In modern times the most famous treasonable plot was the Cato Street Conspiracy in 1820. It was a time of unrest. The economic and social troubles which followed the long war with Napoleon caused widespread discontent and gave agitators their chance. The leader of the conspiracy was Arthur Thistlewood, a revolutionary fanatic. He gathered a gang of kindred spirits, and formed a plot to assassinate the ministers, seize the Bank, the Mansion House and the Tower, and proclaim a provisional government. The massacre of the ministers was to take place on the occasion of a dinner party at the house of Lord Harrowby in Grosvenor Square. The Government, however, had excellent information; on the evening of the dinner party the police raided the headquarters of the conspiracy in Cato Street, Edgware Road. Thistlewood and four of his associates were hanged.