What were the effects of the english civil war

Charles I(from the Stuart Dynasty) was executed publicly, which was the first time in European history that a ruler was executed by his own people. Oliver Cromwell purged Parliament and created a "rump parliament"; only one-fifth of the members remained. England was under the dictatorship of Cromwell until 1659, when Cromwell's son Richard resigned and the Stuarts retook power under Charles II.

Apart from cementing into place the idea of a democratic monastery whereby the head of state is not political and decisions are made by an elected body of people who represent the people. 
It also lead to the freedom of religion act, which brought into legal existence many religions that are still popular to this day, Baptists, Quakers and Presbyterians being three of the most well known to this day.