Was the closing down of Parliament for eleven years the most important reason for the English Civil War?
The suspension of Parliament was not significant in the cause of the Civil war, the events show a civil war would have happened anyway. The king suspended parliament because it challenged his power. It may have caused parliament to resent the kings power, but there was already resentment to the king and the way he ruled the nation.
A long term reason for the civil war was the struggle between Catholicism and Protestantism. Although Charles was protestant the marriage to Henretta Maria, a catholic, showed he was strongly sympathetic to the catholic church. Most people were protestant at that time. They were worried that the church would become more catholic and that the heirs were being brought up as Catholics. An example of the publics opinion was shown when Charles introduced a new prayer book in Scotland. This caused a widespread rebellion that started a war with Scotland.