Four hundred and eight years ago, a Catholic plot to blow up the British Houses of Lords and with it the King of England failed completely. Although a non-event, the attempted bombing had a huge legacy. There was the historical impact, with King James I using it as an excuse to crack down on England's non-conforming Catholics and lay the foundations of a unified British state. There was the cultural impact, with Nov. 5 celebrated ever since with fires and fireworks as Bonfire Night or, in tribute to the plotter caught red-handed, as Guy Fawkes Night. There is a significant linguistic legacy too: the creation of the word "guy."
The word "guy," as used today to indicate a "man, fellow, person, individual, creature," didn't exist in 1605. In fact, even the name Guy, a name with Norman French origins given to poor Guy Fawkes by his parents in 1570, was relatively rare in England at the time, according to the book "Remember, Remember" by James Sharpe—"Guy" himself had actually given up the name in 1603 and went by the name "Guido" instead.
With the arrest of Guy Fawkes shortly after midnight Nov. 5, 1605 (a tip-off to a Catholic member of parliament led to an inspection of the cellars under parliament), however, it soon became an infamous name. Fawkes originally gave his captors the name "John Johnson," but after a couple of days of horrific torture in the Tower of London, he gave himself and his co-conspirators up. He was hanged, drawn, and quartered, with his remains sent to the four corners of the kingdom as a warning to future plotters.
What's more, Nov. 5 was immediately established as a day of celebration, and while little is known about how exactly it was celebrated then, it gradually evolved into a nationalistic night of fireworks and bonfires, with effigies of Catholic figures such as Fawkes and even the Pope set alight. Because of this tradition, the word "guy" began to be used in England to mean "effigy" and later came to be used in a pejorative sense to describe a man ("he's a bad guy") or a usually a "weirdly dressed person," according to Parliament's history of Guy Fawkes Night.
At some point it spread to the United States, where, perhaps due to the lack of context, it began to be used in a wide variety of ways, not all negative. That American English usage later returned to United Kingdom, where it became common to use it to mean "man" or "person." Indeed, the evolution of the word continues today as people debate whether you can call a group that includes females "guys" or even if you can call an individual woman a "guy."
While the word "guy" has changed, so has the reputation of Guy Fawkes, from a minor player in a Catholic plot, to a symbol of terrorism, to a strange figure in a British celebration, to—following the iconic portrayal of a futuristic Guy Fawkes in the comic book "V For Vendetta"—a global symbol of protest and anonymity.