The English Civil War has many causes but the personality of Charles I must be counted as one of the major reasons. Few people could have predicted that the civil war, that started in 1642, would have ended with the public execution of Charles. His most famous opponent in this war was Oliver Cromwell - one of the men who signed the death warrant of Charles.
As with many wars, there are long and short term causes.
long term causes
The status of the monarchy had started to decline under the reign of James I. He was known as the "wisest fool in Christendom". James was a firm believer in the "divine right of kings". This was a belief that God had made someone a king and as God could not be wrong, neither could anyone appointed by him to rule a nation. James expected Parliament to do as he wanted; he did not expect it to argue with any of his decisions.
However, Parliament had one major advantage over James - they had money and he was continually short of it. Parliament and James clashed over custom duties. This was one source of James income but Parliament told him that he could not collect it without their permission. In 1611, James suspended Parliament and it did not meet for another 10 years. James used his friends to run the country and they were rewarded with titles. This caused great offence to those Members of Parliament who believed that they had the right to run the country.
In 1621, James re-called Parliament to discuss the future marriage of his son, Charles, to a Spanish princess. Parliament was outraged. If such a marriage occurred, would the children from it be brought up as Catholics? Spain was still not considered a friendly nation to England and many still remembered 1588 and the Spanish Armada. The marriage never took place but the damaged relationship between king and Parliament was never mended by the time James died in 1625.
Short term causes
Charles had a very different personality compared to James. Charles was arrogant, conceited and a strong believer in the divine rights of kings. He had witnessed the damaged relationship between his father and Parliament, and considered that Parliament was entirely at fault. He found it difficult to believe that a king could be wrong. His conceit and arrogance were eventually to lead to his execution.
From 1625 to 1629, Charles argued with parliament over most issues, but money and religion were the most common causes of arguments.
In 1629, Charles copied his father. He refused to let Parliament meet. Members of Parliament arrived at Westminster to find that the doors had been locked with large chains and padlocks. They were locked out for eleven years - a period they called the Eleven Years Tyranny.
Charles ruled by using the Court of Star Chamber. To raise money for the king, the Court heavily fined those brought before it. Rich men were persuaded to buy titles. If they refused to do so, they were fined the same sum of money it would have cost for a title anyway!
more shorts term.
In 1635 Charles ordered that everyone in the country should pay Ship Money. This was historically a tax paid by coastal towns and villages to pay for the upkeep of the navy. The logic was that coastal areas most benefited from the navy's protection. Charles decided that everyone in the kingdom benefited from the navy's protection and that everyone should pay.
In one sense, Charles was correct, but such was the relationship between him and the powerful men of the kingdom, that this issue caused a huge argument between both sides. One of the more powerful men in the nation was John Hampden. He had been a Member of Parliament. He refused to pay the new tax as Parliament had not agreed to it. At this time Parliament was also not sitting as Charles had locked the MP's out. Hampden was put on trial and found guilty. However, he had become a hero for standing up to the king. There is no record of any Ship Money being extensively collected in the areas Charles had wanted it extended to.
Charles also clashed with the Scots. He ordered that they should use a new prayer book for their church services. This angered the Scots so much that they invaded England in 1639. As Charles was short of money to fight the Scots, he had to recall Parliament in 1640 as only they had the necessary money needed to fight a war and the required authority to collect extra money.
more short term
In return for the money and as a display of their power, Parliament called for the execution of "Black Tom Tyrant" - the Earl of Strafford, one of the top advisors of Charles. After a trial, Strafford was executed in 1641. Parliament also demanded that Charles get rid of the Court of Star Chamber.
By 1642, relations between Parliament and Charles had become very bad. Charles had to do as Parliament wished as they had the ability to raise the money that Charles needed. However, as a firm believer in the "divine right of kings", such a relationship was unacceptable to Charles.In 1642, he went to Parliament with 300 soldiers to arrest his five biggest critics. Someone close to the king had already tipped off Parliament that these men were about to be arrested and they had already fled to the safety of the city of London where they could easily hide from the king. However, Charles had shown his true side. Members of Parliament represented the people. Here was Charles attempting to arrest five Members of Parliament simply because they dared to criticise him. If Charles was prepared to arrest five Members of Parliament, how many others were not safe? Even Charles realised that things had broken down between him and Parliament. Only six days after trying to arrest the five Members of Parliament, Charles left London to head for Oxford to raise an army to fight Parliament for control of England. A civil war could not be avoided.