He was an Englishman who lived in the last 16th Century and early 17th Century. In 1605, he and a group of English Catholics planned to kill King James I of England by blowing up the House of Lords when the King was giving a speech at the opening of Parliament. The plot failed, and he and the other plotters were arrested and executed for treason. The plot occurred on November 5th, so we've since celebrated the day by burning effigies of Guy Fawkes and parade them through the streets.