Eight people (or ten, see below) were executed for involvement in the gunpowder plot.
Everard Digby, Robert Wintour, John Grant, and Thomas Bates were hanged and then cut down and castrated, disembowelled, and then quartered on January 30th.
The next day Thomas Wintour, Ambrose Rookwood, Robert Keyes, and Guy Fawkes were hanged, drawn, and quartered.
Steven Littleton and Henry Garnet were executed some time later.
Robert Catesby and Thomas Percy were killed trying to escape after the plot was exposed. However their bodies were exhumed so that they also could be decapitated. It is debatable as to whether or not this can be counted as an execution, so I have not included it in the tally above.
They were executed, specifically by being hung, drawn and quartered. That is as horrible as it sounds.
Guy Fawkes was a Catholic explosives expert and could set off gunpowder without being killed
Other people.
Christians
The gunpowder was being hidden in the gunpowder plot. It was hidden in a cellar under the house of parliament.
Yes, Socrates was executed by drinking a cup of poisonous hemlock in 399 BC. He was sentenced to death by an Athenian court on charges of corrupting the youth and impiety.
Many people were but one of the most famous fables was that David Crockett was executed after being overwhelmed.
In the Stuart time families went to watch people being executed.
People were being executed for reasons other than actually being guilty.
Being fined, tortured, imprisoned, and executed (although not all of them all the time).
GUnpowder made Castles obsolete. More people were injuried by the stones being blasted apart then were being protected by the ramparts.
It is because Robespierre executed many people who were suspected of being against the revolution.