The whole thing comes from a dispute between Roman Catholics and Protestants. After Henry VIII split from the Roman Catholic church over a divorce dispute and founded his own Anglican church, with the king being head of the church, all of his subjects had to swear an oath on him as the head of church. Who objected was thrown into jail. Also RC
church property was confiscated under chancellor Thomas Cromwell.
Under his successor, young Edward IV
, the division was even more pronounced through the adoption of a newly translated version of the Bible. At the same time radical Protestants hunted Catholics for what they considered to be idoltry (statues of Christ, and Mary etc.).
After edward´s death (he was always sickly and died very young), mary Tudor, a staunch Catholic, became queen. She was also married to a Spanish prince and tried, with the help of the Spanish, to restore the Roman Catholic church as the state religion. She did this very clumsily by reintroducing the inquisition and now persecuted Protestants.
After she died, there was a period of religious chaos, with hardliners of both religions killing each other. Queen Elisabeth I managed to restore order, on oner hand by slapping down on the more radical Protestants (who, because they were angry that they were not allowed to burn Catholics at the stake anymore, moved to America on the Mayflower, they were the Puritans), and at the same time by banning Catholics from public office. Additionaly everybody had to swear an oath on her, refusal was punishable by death. Catholics were also banned from political positions, like becoming MPs. This was mostly a popular reaction on Catholics previously cooperating with an external enemy (the Spanish).
Of course, her and her successor´spolitics were not liked by everybody. A militant group of 12 Catholics decided to blow up the Protestant parliament, free imprisoned Sir Walther Raleigh from the Tower of London and install a Catholic king.
Guy Fawkes was a veteran mercenary and former miner, who used to fight for the Spanish in Flanders as a sapper. Due to his knowledge in using explosives he was chosen to execute the plan.