The 4th Earl of Morton became Regent of Scotland in 1572, for the infant James VI and I. However, once James VI reached the age of majority, the 4th Earl was implicated in the murder of James' father, Lord Darnley in 1567, and was executed in 1581. The earldom was attainted between 1581 and 1586, although the nephew-in-law of the 4th earl (also grandson of the 3rd earl), John Maxwell, 8th Lord Maxwell (1552–1593) was created Earl of Morton in 1581, and continued to use the title until his death. Although Archibald Douglas, 8th Earl of Angus (1555–1588) was confirmed as 5th Earl of Morton in 1586, Lord Maxwell's title of Morton, which had been revoked in 1585, was revived in 1587 and 1592. As a result, two families were in possession of the Earldom, and a conflict arose. This continued into the time of the 7th Earl of Morton (1582–1648), when John Maxwell, 9th Lord Maxwell (c. 1586–1613), also claimed the earldom. Lord Maxwell, however, was attainted in 1609 and his rights then failed, his titles and estates being restored in 1618 to his brother Robert, with the title of Earl of Nithsdale (1620) in lieu of Morton.