James VI and I was a major advocate of a single parliament for England and Scotland.
James VI and I ( 19 June 1566 -- 27 March 1625 ) was King of Scotland as James VI from 24 July 1567 and King of England and Ireland as James I from the union of the Scottish and English crowns on 24 March 1603 until his death . The kingdoms of Scotland and England were individual sovereign states , with their own parliaments , judiciary , and laws , though both were ruled by James in personal union . He was a major advocate of a single parliament for England and Scotland . He achieved most of his aims in Scotland but faced great difficulties in England , including the Gunpowder Plot in 1605 and repeated conflicts with the English Parliament .