In 1629 Monk went to the Netherlands, then a centre of warfare, and there he gained a high reputation as a leader and a disciplinarian. In 1638 he threw up his commission in consequence of a quarrel with the civil authorities of Dordrecht, and returned to England. He obtained the lieutenant-colonelcy of Newport's regiment.
During the operations on the Scottish border in the Bishops' Wars (1639 - 1640) he showed his skill and coolness in the dispositions by which he saved the English artillery at the Battle of Newburn (1640), though himself destitute of ammunition.
At the outbreak of the Irish rebellion (1641) Monk became colonel of Lord Leicester's regiment. All the qualities for which he was noted through life - his talent of making himself indispensable, his imperturbable temper and his impenetrable secrecy - were fully displayed in this post. The governorship of Dublin stood vacant, and Leicester appointed Monk. But Charles I overruled the appointment in favour of Lord Lambart, and Monk with great shrewdness gave up his claims. Ormonde, however, who viewed him with suspicion as one of the two officers who refused the oath to support the Royal cause in England, sent him under guard to Bristol. But he justified himself to Charles in person, and his soldierly criticisms on the conduct of the Irish war impressed the king, who gave him a command in the corps sent over from Ireland during the English Civil War. Monk was, however, soon taken prisoner, at Nantwich (1644), and spent the next two years in the Tower, where he found it difficult to live owing to his want of means. The king himself sent him 100 pounds, a gift for which Monk himself was sincerely grateful. He spent his imprisonment writing his Observations on Military and Political Affairs.
Monk's Irish experience, however, led to his release and an invitation to take service in the parliament's army against the Irish rebels. Making a distinction like other soldiers of the time between fighting the Irish and taking arms against the king, he accepted the offer and took the covenant. At first as adjutant-general to the Parliamentary lord-lieutenant, his old friend Lord Lisle, and afterwards as governor of Ulster, he rendered great services to his new masters. In conjunction with Colonel Michael Jones, governor of Leinster, he made headway against the rebels for two years, but in the third (1649) the Parliamentarians, weakened by defections brought about by the execution of the king, were no longer able to keep the field. Losing one strong place after another, Monk concluded an armistice with the rebel Owen Roe O'Neill upon terms which he knew the parliament would not ratify. The convention was indeed a military expedient to deal with a military necessity, and although most of his army went over to the Royalist cause, he himself remained faithful to his employers and returned to England.
As he expected, Parliament "utterly disapproved" of the armistice but exonerated their general. His next service was in Oliver Cromwell's army in Scotland. He commanded a brigade at the great victory of Dunbar, and afterwards captured a number of small places. When in 1651 Cromwell with the field army hurried southward into England to bring the invading Scots to battle, Monk was left behind to complete the subjugation of the country.
In February 1652 Monk left Scotland to recover his broken health at Bath, and in November of the same year he became an admiral, or rather a "general at sea", instead of a soldier in the First Anglo-Dutch War. Ten days after hoisting his flag for the first time he was engaged with his colleagues, Robert Blake and Richard Deane, in the battle of Portland (28 February - 2 March 1653). In the Battle of the Gabbard (2 - 3 June 1653) Monk exercised the general command after Deane's death. The Battle of Scheveningen followed on 29 - 31 July, which proved a decisive victory for the Commonwealth's fleet.
On his return to shore Monk married Anne Clarges, a woman of "low extraction", often supposed to have been his mistress, "ever a plain homely dowdy", says Pepys, who, like other writers who mention her, is usually still less complimentary. Next year he returned to Scotland, methodically beating down a Royalist insurrection in the Highlands, and when this service was over settled down to a steady government of that country for the next five years.
The timely discovery of a plot fomented by Overton, his second in command, in 1654, gave him an excuse for thoroughly purging his army of all Anabaptists, Fifth monarchy men, and other "dangerous" enthusiasts.
It is improbable that at this time Monk had proposed to himself the restoration of the king, though so astute a diplomatist must have weighed the chances of such an event. His very reticence, however, caused alarm on one side and hope on the other. In 1655 he received a letter from Charles II, a copy of which he at once sent to Cromwell, who is said to have written to him in 1657 in the following terms: "There be that tell me that there is a certain cunning fellow in Scotland called George Monk, who is said to lye in wait there to introduce Charles Stuart; I pray you, use your diligence to apprehend him, and send him up to me." Monk's personal relations with Cromwell were those of sincere friendship on both sides.
During the confusion which followed Cromwell's death (3 September 1658), Monk remained silent and watchful at Edinburgh, careful only to secure his hold on his troops. At first he contemplated armed support of Richard Cromwell, but gave up this idea on realising the young man's incapacity for government, and renewed his waiting policy. In July 1659 direct and tempting proposals were again made to him by the king. Monk's brother Nicholas, a clergyman, was employed by Sir J. Grenvil to bring to him the substance of Charles's letter. No bribe, however, could induce him to act one moment before the right time. He bade his brother go back to his books, and refused to entertain any proposal. But when Booth rose in Cheshire for the king, so tempting did the opportunity seem that he was on the point of joining forces with him, and a manifesto was prepared. His habitual caution, however, induced him to wait until the next post from England, and the next post brought news of Booth's defeat.
For a moment he thought of retiring into private life, but soon Charles Fleetwood and John Lambert declared against the Parliament, and to their surprise Monk not only refused to join them, but (23 October 1659) at once took measures of active opposition. Securing his hold on Scotland by a small but trusty corps of occupation, he crossed the border with the rest of his army. Holding Lambert in play without fighting until his army began to melt away for want of pay, Monk received the commission of commander-in-chief of the parliamentary forces (24 November 1659). The navy, some of the English garrisons and the army in Ireland declared for the parliament, and the army from Scotland crossed the Tweed on 2 January 1660. It was inferior in numbers, but in all other respects superior to Lambert's, and Monk slowly marched on to London, disbanding or taking over on his way the detachments of Lambert's army which he met, and entered the capital on 3 February 1660. In all this his ultimate purpose remained mysterious. At one moment he secretly encouraged the demands of the Royalist City of London, at another he urged submission to the existing parliament, then again he refused to swear an oath abjuring the house of Stuart, and further he hinted to the attenuated Long Parliament the urgent necessity of a dissolution. Lastly, acting as the stern military agent of the infuriated parliament, he took away the gates and portcullises of the city. This angered not only the citizens but his own army, and gave him the lever that he desired to enforce the dissolution of parliament, while at the same time enabling him to break up, as a matter affecting discipline, the political camarillas that had formed in his own regiments. He was now master of the situation, and though he protested his adherence to republican principles, it was a matter of common knowledge that the new parliament, which Monk was imposing on the remnant of the old, would have a strong Royalist colour. Monk himself was now in communication with Charles II, whose Declaration of Breda was based on Monk's recommendations. The new parliament met on 25 April 1660, and on 1 May 1660 voted the restoration of the monarchy.
With the Restoration the historic interest of Monk's career ceases. Soldier as he was, he had played the difficult game of diplomacy with incomparable skill, and had won it without firing a shot. That he was victor sine sanguine, as the preamble of his patent of nobility stated, was felt by every one to be the greatest service of all. He became gentleman of the bedchamber, knight of the Garter, master of the horse and commander-in-chief. Charles raised him to the peerage with the titles of Baron Monk, earl of Torrington and duke of Albemarle, and he received a pension of £7000 a year. As long as the army existed of which he was the idol, and of which the last service was to suppress Thomas Venner's revolt (January 1661), he remained a person of influence. But he entirely concurred in its disbandment, and only the regiment of which he was colonel, the Coldstream (Guards), survives to represent the army of the English Civil War.
In 1664 Monk had charge of the admiralty when James, duke of York, commanded the fleet, and when in 1665 much of the populace deserted London on account of the Great Plague, Monk, with all the readiness of a man accustomed to obey without thinking of risk, remained in charge of the government of the city.
Once more, at the end of 1665, he was called upon to fight, having a joint commission with Prince Rupert against the Dutch in the Second Anglo-Dutch War. The whole burden of the preparations fell upon him. On 23 April 1666 the admirals joined the fleet, and on 1 June 1666 began the great four days' battle, in which Monk showed not only all his old coolness and skill, but also a reckless daring which had seemed hitherto foreign to his character. Later in the same year he maintained order in the city of London during the Great Fire.
His last service occurred in 1667, when the Dutch fleet sailed up the Thames, and Monk, though ill, hurried to Chatham to oppose their farther progress. From that time he lived generally privately (although he officially served as First Commissioner of the Treasury) and died of dropsy on 3 January 1670, "like a Roman general with all his officers about him".
His dukedom became extinct on the death of his son Christopher, 2nd duke of Albemarle (1653 - 1688).
See the Life of Monk, by Dr Gumble, his chaplain (London, 1671).
Original text from http://1911encyclopedia.org