James' son, Charles I, was very interested in art and created one of Europe's greatest art collections. He married Henrietta Maria, the Catholic daughter of the King of France. Like his father he ruled without Parliament under the divine right of the king, but he needed to ask to Parliament for money, so when they refused to give him money he elected the so-called Long Parliament, which also reflected the change in wealth that England had. Only when the Parliament tried to obtain power over the king, this last one killed five of his opponents and declared war, the Civil War had begun.
This struggle, which took place between 1642 and 1649, was fought by Royalists (which represented the Stuart absolutism and the aristocracy) and the Parlamentarians, also called Roundheads because they considered sinful to have long hair so they cut theirs short (which represented the middle class). The Parlamentarian army was stronger, with professional soldiers, better armed and equipped and good trained, so that Charles I was captured and condemned to death
Here, the Parliament declared a republic, the Commonwealth. The House of Lords was abolished and Cromwell took the power. Parliament's army was used for a campaign of repression which culminated in the slaughter of the citizens of Drogheda. He divided the country in 11 regions and adopted puritan rules, like the execution for adultery. Dances, games, theatre performances were banned and pubs and theatres were closed. In 1651 Parliament had passed the Navigation Acts, giving a sort of monopoly of trade to British ships. When Cromwell died in 1658, the army decided to invide Charles II, King of Scotland and Charles I's son, to come back from France and so the monarchy was restored