Hepburn acted with becoming spirit in leaving the service of a prince by whom (though he loved and respected him) he considered himself injured; for he was too true a cavalier and soldier to permit the slightest insult to pass. "It was under these circumstances,” says Harte, who is somewhat slow of admitting the merit of Scottish officers, "that Tilly lost the battle of Leipzig; and the valiant Hepburn resigned his commission, and refused to be reconciled to a master who condescended to ask the continuance of his friendship.” The command of the Green Brigade now devolved upon his friend and companion, Lieutenant-Colonel Robert Munro; but as it was impossible for Hepburn to leave the beleaguered town of Nuremberg, environed as it was by the army of Wallenstein—whose wild Croats scoured all the surrounding country—like the Marquis of Hamilton, he contented himself by remaining as a spectator of those scenes amid which, but for that unfortunate quarrel, he would have shone the foremost.

The guards were always doubled at night, and the perdues, or advanced sentinels, were posted so far as half a mile from the trenches in the direction of the enemy. The ramparts of Nuremberg bristled with pikes, and the whole vast force of Gustavus was ever on the alert. The fleet-mounted Croats were always on the prowl, scouring every road that led to the town; and in one day Colonel Munro lost three servants and five of his horses, taken by their riders; and so great became the scarcity of forage, by their vigilance, that many officers abandoned their chargers and served on foot.

Munro was made full colonel of the regiment he had so long commanded as second: his commission was dated 18th August. Major John Sinclair received the lieutenant-colonelcy, and Captain William Stewart the majority of the battalion, which the casualties of war had reduced to seven companies.

The great suffering produced by want of proper supplies rendered it necessary for Gustavus to employ his vast army in active operations. On the 22d August he erected three strong batteries along the banks of the Rednitz, from which he cannonaded the Imperialists during the whole of that day; but Wallenstein remained immovable, for he had resolved by the mere force of famine to overcome the valour of the Swedish army.

Intrusting his strong camp to the militia of Nuremberg, Gustavus, on the festival of St Bartholomew, the fifty-eighth day of his encampment, crossed the Rednitz with his whole army in order of battle, and took up a new position near the small town of Furth, which placed him exactly on the left flank of the Imperialists.

On this day Hepburn, having resigned, had no command; but, when such an encounter was to take place, could he remain behind in Nuremberg? Arming himself completely in his magnificent suit of inlaid armour, a close casque with gorget, breast and back-pieces, pauldrons, vambraces, and gauntlets, with pistols at his saddle, as if going on service, he mounted his charger, and rode near the King by the side of Major-General Rusteine. But though no longer at their head, he was as much exposed as his old comrades of the Green Brigade, for, as the troops advanced, the major-general was shot near him.

Posted on the steep and rocky heights of the Alta Feste, and that crowned by the ruined Altenburg, with the Biber and the Rednitz flowing at their base, the whole intrenched and palisaded position of the Imperialists shone with long lines of polished helmets, that glinted above the green breastworks and hastily-constructed barricades. Tall pikes and polished arquebusses glittered incessantly in the sunshine, and the brass muzzles of eighty pieces of cannon peered forth from under the shade of every rock, bush, and tree. Here and there, in the foreground, a circle of crows or ravens, wheeling above the long grass, marked where lay a dead horse or unburied soldier, shot in some recent skirmish.

As the dense battalions of the Swedes approached, a tremendous cannonade began. The musketeers and arquebusiers volleyed from flank to flank, and the roar seemed as if it would rend heaven; while the whole hills, from the river at their base to the ruins on the Altenburg, were sheeted with fire and enveloped in snow-white smoke.

Hepburn still continued to look on as a mere spectator amid that terrible cannonade, which was ploughing the earth under his horse’s feet, and mowing down the columns like grass around him, even when a part of his old brigade advanced to storm the ruined fortress, the highest point of those hills from the summit of which Wallenstein, calmly and securely, from his artillery shrouded in smoke, poured fire and death upon the plain below. And now came the tug of war, to which the great battles of Prague and Fleura, Leipzig and the Lech, were but holiday reviews.

Resolving at once on the point of attack, Gustavus ordered four columns, each consisting of five hundred men, to assail the old fortress,

“I will not believe there is a God in heaven if they take that castle from me!” said the energetic but impious Wallenstein, as he shaded his eyes with the peak of his helmet, and observed this movement with confident disdain.

Selected from different regiments, these two thousand "chosen musketeers, mostly Scotsmen,” says Colonel Mitchell, "as an old Nuremberg writer of the period informs us,” left their colours at the foot of the mountains, and, supported by a column of pikes, advanced under a tremendous fire from eighty pieces of ordnance to storm the enemy’s works. Crashing through steel and bone, rending limbs and trunks to shreds and fragments, whole sections of them were swept into eternity. But still the main body pressed gallantly forward, clambering up the steep natural glacis with ardour for the Scots knew well that, if they failed, no other troops would attempt it. "Exposed to the whole fire of the enemy’s artillery, and infuriated by the prospect of immediate death,” says Schiller, "these intrepid warriors rushed forward to storm the heights, which were in an instant converted into a flaming volcano.”

But their bravest efforts were unavailing: no impression could be made on troops so well protected by works which nature and art had strengthened to the utmost. They were compelled to halt, to waver, to make one more desperate attempt, and then retire down the steep precipices over which their killed and wounded were rolling in scores.

Five other columns were successively ordered up to the assault, and five times they were swept away; and vast piles of their dead and wounded rose by the water side ere the attack on the mountain trenches was finally abandoned.

In the mean time a sharp conflict had taken place between the Imperial cavalry and the Swedish left wing, which rested among the thickets of the Rednitz; and during these operations, Wallenstein on one side and the Duke of Saxe-Weimar on the other had each a horse shot under him; while Gustavus had one of his large jack-boots torn off by a cannon-ball.

Sheathed in bright armour, Wallenstein’s cuirassiers, the very flower of his army, filed forth from the trenches at full speed, and, forming squadrons, came on unseen among the smoke. Riding right through a column of Swedish infantry, cutting them down in every direction, they captured General Tortensohn; while, as if to counterbalance this partial success, Cronenberg’s Invincibles —a magnificent regiment of fifteen hundred heavily-mailed horsemen, who attacked only two hundred Finland troopers—were routed and pursued by them under the very cannon of the Altenburg. The hills and the valley through which the Rednitz ran were enveloped in smoke, and the din of the cannon and musketry was incessant. Eighty heavy ordnance, we have said, boomed without intermission from the Imperial lines; and those of Gustavus replied that day by two hundred thousand rounds—a quantity that seems almost incredible.

Of all the attacks made on Wallenstein none appeared so practicable as one proposed by Duke Bernard, who communicated it by his aide-de-camp.

"Is there no able officer who will hasten there, and examine this ground for me?” said Gustavus, looking round him as the cavalier rode off; but so great was the confusion and slaughter that none appeared at hand save the brave Hepburn, who, generously forgetting his quarrel, made an immediate tender of his services.

"Go, Colonel Hepburn,” replied the King gratefully; "I am much obliged to you.”

Dashing spurs into his horse, Hepburn galloped across the field, which was still swept by the fire of the Imperialists; and, by the light of the evening sun, having reconnoitred the approach as well as the thick vapour that overspread it would permit, he returned to the King —losing by the way a faithful sergeant who had followed him, who was shot by his side.

"Sir," replied Gustavus, after he saw the hill himself, "you have made me a true and faithful report, yet I must not make my principal impression here; it demands, at least, my whole body of infantry, and then the artillery and cavalry are left at the mercy of the enemy, who may thus, if he choses, assault me in two places at once.”

Duke Bernard’s troops, among which were still the Scottish regiments of Hamilton and Bellenden, carried the hill by storm, driving back the Imperialists with great loss; and five hundred musketeers of the Green Brigade under Colonel Munro pushed gallantly forward, and posted themselves far in advance, keeping possession of the ground they had gained until five hundred more of their comrades, under Lieutenant-Colonel John Sinclair, came up to strengthen them: and these thousand Scots maintained their dangerous post all night. Colonel Munro was severely wounded in the left side by the “clicket” of his rapier, which a ball had driven against his coat of mail, battering it fiat; Captain Patrick Innes, having exposed himself by flourishing his sword and crying "Vive Gustavus” received a ball in the helmet, which pierced his brain; Lieutenant-Colonel Mackean was killed; Captain Traill, of Lord Spynie’s regiment, received a shot which pierced his throat and gorget of steel through and through; Captain Yaus, of Foulis’s regiment, was struck in the shoulder; Hector Munro, of Catvall, was shot through the head; and an immense number of other Scottish officers and soldiers were killed and wounded.

Gustavus lost one Major-General and many Lieutenant-Colonels, among whom was the Count Erpaah, (a prince of the Empire) whose post, according to some accounts, Hepburn is said to have taken at the royal request during the engagement; while the loss on each side appears to have been about two thousand five hundred killed and wounded.1

Another account says that Wallenstein had four thousand killed and “neare sixe thousand wounded, so that all the hospitalls and lazarettos were sufficientlie filled.”

"Our briggads of foote had scarce bodies of pikemen left to guard their colours,” says Munro; and the musketeers had suffered in an equal degree.

Night was now coming on, and several Swedish regiments which had advanced too far by the base of the hills were in danger of being cut off by Wallenstein’s cavalry, as they were too spirited and too highly disciplined to retire without an order. Gustavus was extremely anxious to communicate that order to them; but the duty seemed fraught with danger, as they were far off, and several masses of the enemy lay between. Trusting to the well-known generosity of the haughty Hepburn, Gustavus in his anxiety applied to him, and, after a few compliments to his character and courage, requested him to "order those regiments to retreat.” "Sire,” replied the brave cavalier, “this is the only service I cannot refuse your Majesty, for it is a hazardous one!” and, drawing his long rapier, rode off to execute the duty!

Elated with this opportunity of gathering fresh laurels, and of distinguishing himself before that royal leader by whom he deemed himself injured, Hepburn once more dashed across the field towards the foot of the mountains, cutting a passage, sword in hand, and by main strength of steed and arm, through the bands of straggling Croats who strove to intercept him, and, delivering the orders of Gustavus to the regiments in question, formed them in column. Although no longer a commissioned officer, they knew and revered him too well to disobey; and he conducted their retreat in so masterly and able a manner that the Imperial cavalry dared not molest them. It was acknowledged by the whole army, that, but for Hepburn’s daring and decision, these troops must have been utterly cut off. He marched them to the King’s post— "And now, sire,” said he, sheathing his rapier, "never more shall this sword be drawn in your service: this is the last time I will ever serve so ungrateful a prince!” Wallenstein still remained immovable within his trenches, and after ten hours of incessant fighting3 the troops of Gustavus drew off. The red fire of the artillery died away; even the pattering reports from the calivers of the hovering Croats ceased; and the twilight darkness of the summer night spread its mantle over the gory rivers, and the corpse-covered approaches to the Imperial camp.