The country round for a vast distance had been long since stripped of provisions, and Gustavus had no course open to him but to march away with his army and leave the city to its fate, or to attack the Imperialists in their stronghold.
On the day after his arrival, the 21st of August, Gustavus marched out and opened a cannonade upon the Imperialists' position, in order to induce Wallenstein to come down and give battle. Wallenstein was not, however, to be tempted, but kept his whole army busy with the spade and axe further intrenching his position. The next day the king brought his guns nearer to the enemy's camp, and for twenty-four hours kept up a heavy fire. The only result, however, was that Wallenstein fell back a few hundred yards on to two ridges, on one of which was the ruined castle called the Alte Veste; the other was known as the Altenburg. The ascent to these was steep and craggy, and they were covered by a thick forest. Here Wallenstein formed in front of his position a threefold barrier of felled trees woven and interlaced with each other, each barrier rising in a semicircle one above the other. Before the Swedish cannon ceased to fire the new position of the Imperialists had been made impregnable.
Unfortunately for Gustavus he had at this moment lost the services of the best officer in his army, Sir John Hepburn, whom he had always regarded as his right hand. The quarrel had arisen from some trifling circumstance, and Gustavus in the heat of the moment made some disparaging allusion to the religion of Hepburn, who was a Catholic and also to that officer's love of dress and finery. The indignant Hepburn at once resigned his commission and swore never again to draw his sword in the service of the king—a resolution to which he adhered, although Gustavus, when his anger cooled, endeavoured in every way to appease the angry soldier.
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.
Steadily and in good order the Scotch and Swedish infantry pressed forward, and forcing the lower ditch strove to climb the rocky heights; but in vain did they strive. Over and over again they reached the intrenchments, but were unable to force their way through the thickly bound fallen trees, while their lines were torn with a storm of iron and lead. Never did the Scottish soldiers of Gustavus fight with greater desperation and valour. Scores of them rolled lifeless down the slope, but fresh men took their places and strove to hack their way through the impenetrable screen through which the Imperialist bullets whistled like hail.
At last, when nigh half their number had fallen, the rest, exhausted, broken, and in disorder, fell suddenly back. Gustavus in person then led on his Finlanders, but these, after a struggle as obstinate and heroic as that of their predecessors, in their turn fell back baffled. The Livonians next made the attempt, but in vain.
In the meantime a sharp conflict had taken place between the Imperial cavalry and the Swedish left wing. Wallenstein's cuirassiers, hidden by the smoke, charged right through a column of Swedish infantry; but this success was counterbalanced by the rout of Cronenberg's Invincibles, a magnificent regiment of 1500 horsemen, by 200 Finland troopers. The troops of Duke Bernhard of Weimar, among whom were still the Scottish regiments of Hamilton and Douglas, marched against the heights which commanded the Alte Veste, and drove back the Imperialists with great loss. Five hundred musketeers of the Green Brigade under Colonel Munro then pushed gallantly forward and posted themselves far in advance, resisting all attempts of the Imperialists to drive them back, until Lieutenant Colonel Sinclair, who was now in command of Munro's own regiment, brought it forward to his assistance. Until the next morning this body of one thousand men maintained the ground they had won in spite of all the efforts of the Imperialists to dislodge them.