As he persisted in his resolution Colonel Munro was appointed to the command of the Green Brigade.  It is probable that the quarrel was the consummation of a long standing grievance.  Hepburn as well as the other Scottish officers had shared the indignation of Sir John Hamilton when the latter resigned in consequence of the Swedish troop being placed in the post of honour at the storm of the castle of Marienburg after the Scots had done all the work.  There had, too, been much discontent among them concerning the Marquis of Hamilton, whom they considered that Gustavus had treated ungenerously; and still more concerning Lieutenant Colonel Douglas, whom Gustavus had committed to a common prison for a slight breach of etiquette, a punishment at which the English ambassador, Sir Harry Vane, remonstrated, and which the whole Scottish officers considered an insult to them and their country.

There were probably faults on both sides.  The Scottish troops were the backbone of the Swedish army, and to them were principally due almost the whole of the successes which Gustavus had gained.  Doubtless they presumed upon the fact, and although Gustavus recognized his obligations, as is shown by the immense number of commands and governorships which he bestowed upon his Scottish officers, he may well have been angered and irritated by the insistance with which they asserted their claims and services.  It was, however, a most unfortunate circumstance that just at this critical moment he should have lost the services of an officer whose prudence was equal to his daring, and who was unquestionably one of the greatest military leaders of his age.

It is probable that had Hepburn remained by his side the king would not have undertaken the attack upon the impregnable position of the Imperialists.  Deprived of the counsellor upon whose advice he had hitherto invariably relied, Gustavus determined to attempt to drive Wallenstein from his position, the decision being finally induced by a ruse of the Imperialist commander, who desired nothing so much as that the Swedes should dash their forces against the terrible position he had prepared for them.  Accordingly on the 24th of August he directed a considerable portion of his force to march away from the rear of his position as if, alarmed at the superior strength of the Swedes, he had determined to abandon the heights he had so long occupied and to march away.

Gustavus fell into the trap, and prepared at once to assault the position.  Two hundred pieces of artillery heralded the advance, which was made by the whole body of the musketeers of the army, drafted from the several brigades and divided into battalions 500 strong, each commanded by a colonel.  It was a terrible position which they were advancing to storm.  Each of the lines of intrenchments was surmounted by rows of polished helmets, while pikes and arquebuses glittered in the sunshine; but it was not long that the scene was visible, for as the battalions approached the foot of the Altenburg 80 pieces of artillery opened from its summit and from the ridge of the Alte Veste, while the smoke of the arquebuses drifted up in a cloud from the lines of intrenchments.