A conspiracy in 1605 in England to blow up James I and the Houses of Parliament to avenge the persecution of Catholics in England; led by Guy Fawkes WordNet 3.0 & Open English WordNet

The Gunpowder Plot of 1605, in earlier centuries often called the Gunpowder Treason Plot or the Jesuit Treason, was an unsuccessful attempted regicide against King James I by a group of English Catholics led by Robert Catesby who considered their actions attempted tyrannicide and who sought regime change in England after decades of religious persecution. Wikipedia

Failed assassination attempt against King James I of England and VI of Scotland Wikidata

A failed plot, in November 1605, to kill the Protestant king James I of England and VI of Scotland, and to blow up the House of Lords using gunpowder, annually commemorated on Guy Fawkes Day. Wiktionary

Failed plot to kill the king of England. Wiktionary (translation)