Charles I threatened the members of Parliament, and sent them home, One of the reasons for this was that he believed in his divine right .
Charles I would rule without Parliament for 11 years, but would soon need the Parliament to be reformed. He asked Parliament if they could raise taxes to pay soldiers to fight against Protestants. Parliament would agree, but on one condition.
The condition would be that for revenge, The Parliament would try and execute Charles I's closest friends, this would make the king furious with Parliament.
So, for revenge, Charles I gathered up a small army to go and kill the members of Parliament. Unfortunately for the king, Parliament was warned that the army was coming, so they escaped. This was the last straw.
So, in retaliation, Parliament declared war on the king. This divided England into 2 parts: the cavaliers, which were led by Charles I, and the roundheads, which were lead by Oliver Cromwell. The two sides fought each other in many battles, such as the Battle of Lostwithiel.
The war lasted about 3 years, but in the end, the roundheads were victorious, after the king was captured , he was tried and executed, this was a shock in Europe because this was the first time an absolute monarch was overthrown by the people.