On 16 January 1572, Thomas Howard, 4th Duke of Norfolk and cousin of Queen Elizabeth, went on trial for his part in the Ridolfi Plot, a scheme to overthrow the Queen and replace her with the Catholic Mary, Queen of Scots. Obviously, it did not go well.
The plot itself was the handiwork of Roberto di Ridolfi, a banker who apparently had way too much time on his hands. He was also rather poorly informed and seemed to be under the impression that at least half of the nobles in England were Catholic and were ready to deliver up nearly 40,000 men for this little scheme of his. He was able to recruit Norfolk by dangling the prospect of Norfolk marrying Mary when she was queen. It also helped that Norfolk was a sulky man-child who felt like Elizabeth didn’t appreciate him enough. This was all especially stupid in light of the fact that Norfolk had just gotten out of prison for scheming to marry Mary the year before. Other northern lords fell into line and the Northern Rebellion was formed. Now it was official and sounded a bit scary, Norfolk tried to call it off. Unfortunately, the other lords listened to him about as much as Elizabeth did.
The rebellion went forward and failed; the leaders were executed and there was a purge of Catholic sympathisers in the priesthood. Norfolk was taken to the Tower of London, where he remained for nine months before begging his way out and promising never to be bad again. He was placed under house arrest and eventually a fed up Elizabeth had him executed for treason. Shortly after the plot was uncovered, the Pope issued a Papal Bull excommunicating Elizabeth. She retaliated by cracking down on Catholics; less than a decade later, Catholicism was abolished throughout England.
Oh, and Ridolfi, the idiot who thought this would be a good idea? He, luckily, wasn’t even in England when the plot was discovered. He became a Florentine senator in 1600 and presumably lived a long and happy life.