James VI, King of Scots
The future James VI, King of Scots, was born on 19 June 1566, son of Mary, Queen of Scots, and Henry, Lord Darnley, King Consort. The following February, his father was murdered in the explosion at Kirk o'Field, and in July his mother was forced to abdicate. She fled to England, never to see her son again. James was at once crowned King of Scots, but a regency had to be put in place until he gained personal control of his kingship in 1583, aged 17. He would be King of Scots for 57 years until his death in England in 1625. In 1603 he was offered the English Crown. This created the United Kingdom, literally, but it did not unite the two countries. That happened with the Union of the Parliaments in 1707.
James brought with him to England that experience of a Reformation which had been swifter, much more decisive and much less violent, and he was anxious to extend toleration to Catholics, but he was quickly disavowed of that by those who formed the English court. He was quickly indoctrinated with the English experience of the preceding century and any intentions of pursuing a tolerant course were completely cured two years later in 1605 when Catholic plotters nearly succeeded in blowing up James and the assembled parliament in the Gunpowder Plot. This led, naturally, to a new upsurge in persecution against English Catholics. Much time, attention and resources of the government of England were taken up trying to contain the activities of rebellious English Catholics, for well over two hundred years.