The basic causes of the English Civil War were lack of money, religion, foreign affairs and the struggle between the monarchy and Parliament, according to the BBC. The conflict broke out during the end of the reign of Charles I in 1642 and concluded in 1649 with the execution of the king. Oliver Cromwell ruled England as Lord Protector until 1658 when the monarchy was re-established by Parliament.
Charles I's lack of money was due to his Scottish upbringing. His father, James I, was the first monarch to rule over Scotland and England, and the family had no wealth. When Charles I went to war against Catholic countries, he asked the people of England for taxes to pay for the conflict. Parliament refused to raise taxes and then blamed the king for failing in the war.
Charles I eventually dissolved Parliament in 1629 because of the conflict regarding lack of tax revenue. He called Parliament back in 1640 when the Scots rebelled and the king needed to raise taxes to quell the uprising. Parliamentary elections overwhelming chose candidates that were against the king's court. Charles I did get his taxes to fight wars, but it came at the price of passing a bill stating Parliament couldn't be dissolved without its own consent.
The final issue leading to the English Civil War was Charles I's attempted arrest of five parliamentary critics in early 1642, according to History Learning Site. The five men had been tipped off and fled before they could be detained. Six days after the attempted arrests, Charles I fled to Oxford to raise an army to fight those loyal to Parliament.