Religion was a huge part of 17th century England, and can be seen as one of the highest contributing factors to the civil war. Most of the country consisted of Protestants with a minority of Catholics, however this did not mean there was no friction between the two.
The religious quarrels began right at the start of Charles' reign, when Charles married Henrietta Maria, a French Catholic. Although Charles didn't choose to marry her - his father, James, set up the marriage - the public, especially the Puritans, didn't like having a Catholic as Queen. A few extremists even saw this as a sign that Charles was secretly Catholic! After the King dissolved Parliament, he made William Laud the Archbishop of Canterbury, in 1633. While Laud was Archbishop, he made many changes to the Church. Most of these changes involved beatifying the Church and bringing back robes for priests, statues and stained-glass windows. All these things reminded the English of Catholicism, and it did not please the Presbyterians (puritans) who believed that church should just be about “you” and God, no extravagance was required and it was considered to be unnecessary.
In 1636, Archbishop Laud decided to introduce the English Prayer Book (which stated how services should be run) into Scotland. There was nationwide rioting, because no one wanted to follow the new Prayer Book. Scotland was a Presbyterian (Puritan) country, and they thought that the English Prayer Book was far too Catholic to use in Scotland. This eventually led to many Scots, called the Covenanters, marching down the country in an attempt to invade England. At this point, Charles had to call Parliament to ask for taxes to pay for the war, but was horrified to see that most of the MPs were on the Covenanters' side. Parliament agreed that the Prayer Book was too Catholic, so