Only one man could be his successor. On the self-same 26th of June Cromwell received his commission as captain-general and commander-in-chief; and two days later he started on his journey to the north. Charles Fleetwood was his lieutenant-general, John Lambert, an excellent soldier, his major-general; and joined to his staff was another officer whom we saw fighting in the Low Countries many years ago, Colonel George Monk. He had served in the Civil War first with the Royalists, and had been taken prisoner by Fairfax at Nantwich in January 1645; he had then passed some time in confinement in the Tower, and finally had taken service with the Parliament in Ireland, where his merit had attracted the attention of Cromwell. Oliver was now anxious to provide him with a regiment; but the corps which he had designed for him was unwilling to receive a Royalist for colonel. Five companies were therefore taken from Sir Arthur Hazelrigg's regiment at Newcastle and as many more from Colonel Fenwick's at Berwick; and the ten companies were united into Monk's regiment of foot. Thus was formed the oldest of our existing national regiments, the one complete relic of the famous New Model,[178] the one surviving corps which fought under Oliver Cromwell, itself more famous under its later name of the Coldstream Guards. On the 19th of July Cromwell halted near Berwick, where he mustered sixteen thousand men, a third of them cavalry; and on the 22nd he crossed the Tweed and marched up the coast upon Edinburgh. A fleet on the east coast provided him with supplies as he advanced, which furnishes an interesting precedent for the system that was to be seen later under Wellington in the Peninsula. On the 28th of July he was at Musselburgh, and on the following morning he came in sight of the Scottish army, which was entrenched along the line from Leith to the Canongate.