James I of England (James VI of Scotland) was a dedicated scholar in his younger years and ruled Scotland well, managing to placate different factions within the country and maintaining the peace in Scotland when only in his teens. He also had to cope with his own sad history; his father Lord Darnley was murdered when James was just a year old and his mother, Mary Queen of Scots was executed under Elizabeth I's direction when he was just 21. Despite this, James maintained the treaty of Berwick which he had signed with Elizabeth I prior to his mother's execution.
As King of England and Ireland from 1603, James I achieved much. He is credited with introducing the King James Bible to England in 1611 which was the standard version of the bible for the following 250 years, and which made the Bible more accessible to commoners. His foreign policy was largely peaceful, in 1604 he ended the war with Spain and attempted peace in Europe through the marriages of his children. He was a good mediator and helped prevent wars on several occasions.
Nevertheless, he displeased both Protestants and Catholics within England. The former for not introducing more radical Puritan policies and the latter for continuing the persecution against them. Indeed it was the Catholics who attempted the foiled gunpowder plot in 1605 to get rid of him.