The exact date on which Karl became king is vague because of the then uncertain political situation. His father was executed on January 30, 1649, which theoretically made him King Charles II. He was proclaimed king of Scotland on 16 February 1649 and king on 16 February 1649, but was also recognized in some British colonies (particularly the colony and the Dominion of Virginia). In Scotland, Charles was only king in the title for some time. It took two years of negotiations with the Presbyterians for him to be finally crowned King of Scotland on 1 January 1651 at Scone. His reign was short-lived, however, as he was soon ousted by the Republican armies under the leadership of Oliver Cromwell. His coronation in England was not made until after Cromwell`s death and the re-establishment of the monarchy in May 1660; Charles spent most of his time in exile in France. Charles`s negotiations continued from his captivity at Carisbrooke Castle on the Isle of Wight (to which he had fled Hampton Court in November 1647) and led to an engagement with the Scots, under which the Scots were to provide an army for Charles in exchange for the imposition of Confederation against England. To which Charles would have replied „that the cause was easy to assume: for his speech was his, his action was that of the ministry.”  On 2 September 1666, what was later called the Great Fire of London again became the need for London.
Although the fire effectively halted the spread of the Great Plague due to the burning of all rats and fleas carrying plague, the fire consumed about 13,200 houses and 87 churches, including St. Paul`s Cathedral. Charles II is known to have joined firefighters in the fight against the fire. In The Hague, Charles had a brief affair with Lucy Walter, who then falsely claimed that they had married in secret. His son James Crofts (then Duke of Monmouth and Duke of Buccleuch) was one of Charles`s many illegitimate children, known in British society.  On his deathbed, Charles asked his brother James to take care of his beloved: „Be good in Portsmouth and don`t let poor Nelly starve.”  He said to his courtships, „I am sorry, gentlemen, for having such a time to die,” and expressed regret for his treatment of his wife. On the last night of his life, he was admitted to the Catholic Church in the presence of Father John Huddleston, although it is not clear to what extent he was fully aware or engaged about it and with whom the idea emerged. On 14 February he was buried in Westminster Abbey „without any splendour.”  As negotiations with the Scots stalled, Charles allowed General Montrose to land with a small army in ordkney to threaten the Scots with an invasion, in the hope of forcing a deal to his liking. Montrose feared that Charles would accept a compromise and therefore decided to invade the Scottish continent anyway.
He was captured and executed. Charles reluctantly promised that he would abide by the terms of an agreement between him and the Scottish Parliament in Breda and that he would support the Solemn League and Covenant, which was approved by the Presbyterian ecclesiastical administration throughout Britain. Arriving in Scotland on 23 June 1650, he formally approved the Convention; his renunciation of the church leadership, although he won in Scotland, left him unpopular in England. Karl himself soon despised the Covenanters` „ignorance” and „hypocrisy.”  In 1678, a retired Anglican cleric named Titus Oates falsely claimed to have uncovered a French-inspired plot to replace Charles II with his Catholic brother James. A wave of anti-Catholic hysteria swept England and did little to help Charles advance the secret agenda he had agreed in the Treaty of Dover. Worse still, the English Parliament decided to continue the law of exclusion that would remove Roman Catholic from the lineage that would succeed him: some wanted to replace him as heir to the throne by the Protestant duke of Monmouth, the eldest of Charles`s illegitimate children.