'Gley-eyed' (squinting) Argyll was the implacable Covenanter whose dour disapproval did so much to alienate Charles II from the Scots. However, he was canny and had immense political perception.
He was born between August 1605 and April 1607 but probably in 1607. In 1618, his father having left the kingdom, the care of the Western Highlands devolved on him; and to him, being a Protestant, his father was directed to make over all his estates. On this occasion his father is reported by Clarendon to have given the following account of him to the king. "Sir, I must know this young man better than you can do; you have brought me low that you may raise him, which I doubt you will live to repent; for he is a man of craft and subtlety and falsehood, and can love no man; and if ever he finds it in his power
to do you a mischief he will be sure to do it."
In 1625 the office of Justice General was conferred on him and his successors, Earls of Argyll, but in 1628 it was resigned by him to the King. Shortly before 6 August 1626 he married his cousin, Lady
Margaret Douglas, and they became the parents of six children. On 14 January 1634 he was one of the Extraordinary Lords of Session. In 1637 Charles I attempted to impose on Scotland Laud's prayer book as it smacked of popery, which aroused the wrath of the Lowland Presbyterians. As a result a 
Covenant was drawn up to protect the Protestant religion and Argyll became the leader of the Covenanters. In 1638 he succeeded to the Earldom and, in 1639, sent 500 Highlanders to swell the covenanting force at Aberdeen; then, in 1640, in the cause of the "Covenant," he carried fire and sword through Atholl, Badenoch, and Angus.
In August 1641 when Charles I came to Scotland, Argyll made his peace with the king and, on 15 November 1641, was created Marquess of Argyll, a pension of 1,000 pounds a year being, at the same time, settled upon him. Soon afterwards he again joined the Covenanters, but was signally defeated by Montrose at Inverlochy and Kilsyth. In October 1648 he conducted Cromwell to Edinburgh, where the "Covenant" was renewed.
After the execution of Charles I, Charles II apparently sent a message to Argyll, suggesting that he would join with the Scots if the Solemn League and Covenant was not pressed upon him. But the
Covenanting Scots insisted on the Oath as a price of their assistance. When Charles II's intrigues to re-impose his ideas on the rebellious Scots were revealed, Argyll took command of the opposition. The
terrible death suffered in 1650 by Montrose, the brilliant Royalist commander, at Argyll's instigation has forever shadowed the latter's reputation.
However, Argyll assisted in bringing Charles II to Scotland in June 1650, having obtained a promise to be made a Duke. On 1 January 1651, when Charles II was crowned in the Cathedral of Scone, he
received the crown from Argyll and the sceptre from the Earl of Crawford, both Covenanters. In the early summer of 1651 King Charles II rode high and Argyll's influence diminished as the king's authority
increased. However, Charles II moved into England with his army but was defeated and forced to escape to the continent.
Argyll was present at the proclamation of Cromwell as Lord Protector and signed a promise to live peacably under that Government. However, in July 1660 he went to London to wait on the newly arrived King Charles II; but this, the last of his many tergiversations, availed him nothing, as he was ordered to the Tower and thence taken to Edinburgh Castle. He was tried for high treason and, on 25 May 1661, sentence pronounced against him when, having been attainted, all his honours became forfeited. On 27 May 1661 he was executed at the Cross of Edinburgh; his head was exposed on the top of the Tolbooth where Montrose's head had been.

Source: Leo van de Pas