Charles I was the son of King James I of England, and succeeded him on the throne in 1625 at the age of 25. He married Princess Henrietta Maria of France later that year, though the two were not crowned together because she was Catholic and he was not.

Like his father, Charles believed in the absolute power of kings and clashed with Parliament on many issues. In 1629 Charles decided to govern without summoning Parliament; he sold monopoly rights and raised taxes rather than having money for himself allotted by Parliament. He did end up summoning a session of Parliament in 1640, where the conflicts became even greater. Charles was unable to resist the demand for the execution of his advisor the Earl of Strafford, but on 4 January 1642 he took the step of entering the House of Commons with an armed guard to arrest the five members of Parliament who were planning to impeach Queen Henrietta. Public opinion turned against him, and Charles fled London.

Those who supported the king were called Royalists or Cavaliers; those against him, Parliamentarians or Roundheads. The two sides met in battle many times and for a year or two the Royalists seemed to be winning; however, the New Model Army led by Oliver Cromwell won some great victories in 1644 and 1645. Charles surrendered to the Scottish in 1646, but they handed him over to the Parliamentarians and he was imprisoned.

He was tried before 135 judges but would not put in a plea because he refused to admit that a king being on trial could be legal. He was found guilty by only 68 votes to 67, and sentenced to death. He was excuted by beheading on 30 January 1649, with many of the people attending doing their best to dip a handkerchief in the blood of the "Martyr King" as some would later call him.

Queen Henrietta and their children were able to make their way to France and remained there until Oliver Cromwell's son Richard was compelled to resign from the leadership of England and the return of Charles' son Charles II was negotiated.