In mid-1642, both sides started travelling around the country to gather supporters and weapons. On 22 August, King Charles raised the royal flag in Nottingham. By doing this, he was announcing that he was at war with Parliament.
The King found more support in the countryside, poorer parts of the country and northern and western England. Parliament found more support in most cities, ports, richer parts of the country and southern and eastern England. People who were secretly Catholic mostly supported the King. The Royal Navy and most Puritans supported Parliament. Some areas supported Parliament because of local problems, such as the land drainage works in The Fens.
The Royalist armies were led by Prince Rupert, the King's nephew. The Parliamentarian armies were at first led by the Earl of Essex. The Royalists decided they would try to fight the Parliamentarians quickly, and so went to meet them in Warwickshire. The first major battle was the Battle of Edgehill in October 1642. The battle ended in a draw. The King tried to return to London but was blocked by the Parliamentarian army. He moved with his armies to Oxford, where he had more loyal followers.
The first year of the war went fairly well for the Royalists. They strengthened their control over the north and west. Their progress was slower in the Midlands, though they did capture Lichfield. After mid-1643, the Parliamentarians started to do better. They won battles in Lincolnshire, in the east and at Newbury to the west of London.
King Charles made a deal with the Irish rebels to stop the fighting in Ireland, freeing up soldiers that could fight for him. Parliament made a deal with the Scottish Covenantors, who would help them. Parliament were also helped by a talented army leader called Oliver Cromwell. He led a cavalry (horse riders) unit called the "Ironsides". The Ironsides were better organised than most cavalry units, which made them far better at fighting.
Helped by the Scots and the Ironsides, Parliament won a major victory the Battle of Marston Moor in July 1644. They took control of northern England. The Royalists were weakened but not yet defeated. They won the Battle of Lostwithiel in Cornwall, defeating Essex's soldiers. They also managed to fight to a draw at a second Battle of Newbury in October.
In 1645, Parliament organised its soldiers into the New Model Army. The Earl of Essex was replaced by Sir Thomas Fairfax. Oliver Cromwell became Fairfax's deputy. The New Model Army was better organised than any army that had come before it. They defeated the King's largest army at the Battle of Naseby in June 1645. Most of the Royalist soldiers at Naseby were taken prisoner.</small> King Charles escaped Naseby but left behind his baggage, which had letters inside them. The Parliamentarians opened them and found out that the King was trying to get help from the Irish Catholics and from Catholic countries. The King lost support because of this.
The other main Royalist army was defeated at the Battle of Langport in Somerset, one month later. The Parliamentarians took control of South West England, where they had been weak. King Charles tried to gather his remaining supporters in the Midlands. Many fortress towns in the area from Oxford to Newark-on-Trent were still loyal to him. In May 1646, Charles met a Scottish army in Nottinghamshire. The Scots took him prisoner.
Although the Parliamentarians had won, they were divided on how to run the country. One big argument was over religion. Most members of Parliament wanted a Presbyterian national church. The New Model Army favoured allowing local churches to run themselves without there being a national church. The defeated Royalists supported the existing Church of England, though some were secretly Catholic. Parliament and the Army both tried to win support of the King and the Scottish Presbyterians. King Charles was in prison and was passed between the groups. He refused to make a deal any of them, because he believed that only he had the right to rule over England. He pretended he was interested in making a deal while he planned to take back control of the country. The divisions became worse when Parliament tried to disband the New Model Army.
A second war broke out when some Scottish Presbyterians (called the Engagers) and some English Presbyterians allied with the King. They agreed to support him in return for making the English and Scottish churches into Presbyterian churches. The Scots invaded England, while Royalist rebellions broke out in various parts of England. Some of the rebellions were defeated very easily. The rebellions in Wales, Kent, Essex and Cumberland were stronger but were put down by the New Model Army. The Royalists and Scots were defeated at the Battle of Preston in August 1648.
The New Model Army was in control. In an event called "Pride's Purge", army Colonel Thomas Pride removed all members of Parliament who had not supported the Army. Only 75 members were left. The Army put them in charge of the country, and this Parliament was called the Rump Parliament.
The Rump Parliament decided they would not work with King Charles any more. They put him on trial. On 27 January 1649, the trial found him guilty of treason and called him a "tyrant, traitor, murderer and public enemy". He was beheaded three days later.
Many historians say that the execution of King Charles was an important moment in English history, and even in the history of the Western World. No European monarch had ever been put on trial by their own people before. Other countries in Europe said the execution was wrong, but they did not do much else. Not all Parliamentarians supported the execution. Fairfax thought it was wrong. He resigned as leader of the New Model Army, and was replaced by Oliver Cromwell.
The next king would have been Charles' son Prince Charles, the future King Charles II. Parliament announced instead that England would become a republic, called the Commonwealth of England. However, Prince Charles could still become King of Scotland.
The third English Civil War was actually more of a fight between Scottish and English armies, and much of it was fought in Scotland.
In 1649, the Marquess of Montrose started a rebellion in Scotland in support of King Charles II. Rather than support Montrose, Charles decided to ally with the Scottish Covenantors. They feared the Commonwealth of England would stop Scotland from having a Presbyterian church. Montrose was defeated by Scottish armies in April 1650. In June, Charles landed in Scotland and signed an agreement with the Scottish Covenantors.
Cromwell travelled to Scotland and arrived the following month. Over the next year, it took control of the main parts of Scotland. When Charles fled to England, Cromwell followed him, leaving George Monck to finish winning the war in Scotland. When this was done, Scotland became part of the Commonwealth of England.
Charles' army marched across England to the western regions where the Royalists had the most support. However, they could not find as many supporters as they wanted. Cromwell found them and defeated them at the Battle of Worcester on 3 September 1651. Charles fled to The Netherlands. He would not return until 1660.
The Irish rebellion that started in 1641 would continue until 1652. It was mainly fought by Irish Catholics against armies of the English Parliamentarians, Scottish Covenantors and Protestant settlers in Ireland. At first the rebels fought English Royalist armies as well, but this mostly stopped after September 1843. Seven months after the rebellion began, the rebels created their own government in Kilkenny. This was known as the Irish Catholic Confederation.
In 1649, Oliver Cromwell went to Ireland and put down their rebellion. Cromwell was remembered in Ireland as a brutal invader, particularly because of the large numbers of people killed at the Siege of Drogheda. Some fighting continued in Ireland until 1653.