So long as such an arm fought for him, the cause of the Elector Frederick was not irretrievably lost. New prospects began to open, and misfortune raised up friends who had been silent during his prosperity. King James of England, who had looked on with indifference while his son-in-law lost the Bohemian crown, was aroused from his insensibility when the very existence of his daughter and grandson was at stake, and the victorious enemy ventured an attack upon the Electorate. Late enough, he at last opened his treasures, and hastened to afford supplies of money and troops, first to the Union, which at that time was defending the Lower Palatinate, and afterwards, when they retired, to Count Mansfeld. By his means his near relation, Christian, King of Denmark, was induced to afford his active support. At the same time, the approaching expiration of the truce between Spain and Holland deprived the Emperor of all the supplies which otherwise he might expect from the side of the Netherlands. More important still was the assistance which the Palatinate received from Transylvania and Hungary. The cessation of hostilities between Gabor and the Emperor was scarcely at an end, when this old and formidable enemy of Austria overran Hungary anew, and caused himself to be crowned king in Presburg. So rapid was his progress that, to protect Austria and Hungary, Boucquoi was obliged to evacuate Bohemia. This brave general met his death at the siege of Neuhausel, as, shortly before, the no less valiant Dampierre had fallen before Presburg. Gabor's march into the Austrian territory was irresistible; the old Count Thurn, and several other distinguished Bohemians, had united their hatred and their strength with this irreconcileable enemy of Austria. A vigorous attack on the side of Germany, while Gabor pressed the Emperor on that of Hungary, might have retrieved the fortunes of Frederick; but, unfortunately, the Bohemians and Germans had always laid down their arms when Gabor took the field; and the latter was always exhausted at the very moment that the former began to recover their vigour.
Meanwhile Frederick had not delayed to join his protector Mansfeld. In disguise he entered the Lower Palatinate, of which the possession was at that time disputed between Mansfeld and the Bavarian general, Tilly, the Upper Palatinate having been long conquered. A ray of hope shone upon him as, from the wreck of the Union, new friends came forward. A former member of the Union, George Frederick, Margrave of Baden, had for some time been engaged in assembling a military force, which soon amounted to a considerable army. Its destination was kept a secret till he suddenly took the field and joined Mansfeld. Before commencing the war, he resigned his Margraviate to his son, in the hope of eluding, by this precaution, the Emperor's revenge, if his enterprize should be unsuccessful. His neighbour, the Duke of Wirtemberg, likewise began to augment his military force. The courage of the Palatine revived, and he laboured assiduously to renew the Protestant Union. It was now time for Tilly to consult for his own safety, and he hastily summoned the Spanish troops, under Corduba, to his assistance. But while the enemy was uniting his strength, Mansfeld and the Margrave separated, and the latter was defeated by the Bavarian general near Wimpfen (1622).
To defend a king whom his nearest relation persecuted, and who was deserted even by his own father-in-law, there had come forward an adventurer without money, and whose very legitimacy was questioned. A sovereign had resigned possessions over which he reigned in peace, to hazard the uncertain fortune of war in behalf of a stranger. And now another soldier of fortune, poor in territorial possessions, but rich in illustrious ancestry, undertook the defence of a cause which the former despaired of. Christian, Duke of Brunswick, administrator of Halberstadt, seemed to have learnt from Count Mansfeld the secret of keeping in the field an army of 20,000 men without money. Impelled by youthful presumption, and influenced partly by the wish of establishing his reputation at the expense of the Roman Catholic priesthood, whom he cordially detested, and partly by a thirst for plunder, he assembled a considerable army in Lower Saxony, under the pretext of espousing the defence of Frederick, and of the liberties of Germany. "God's Friend, Priest's Foe", was the motto he chose for his coinage, which was struck out of church plate; and his conduct belied one half at least of the device.
The progress of these banditti was, as usual, marked by the most frightful devastation. Enriched by the spoils of the chapters of Lower Saxony and Westphalia, they gathered strength to plunder the bishoprics upon the Upper Rhine. Driven from thence, both by friends and foes, the Administrator approached the town of Hoechst on the Maine, which he crossed after a murderous action with Tilly, who disputed with him the passage of the river. With the loss of half his army he reached the opposite bank, where he quickly collected his shattered troops, and formed a junction with Mansfeld. Pursued by Tilly, this united host threw itself again into Alsace, to repeat their former ravages. While the Elector Frederick followed, almost like a fugitive mendicant, this swarm of plunderers which acknowledged him as its lord, and dignified itself with his name, his friends were busily endeavouring to effect a reconciliation between him and the Emperor. Ferdinand took care not to deprive them of all hope of seeing the Palatine restored to his dominion. Full of artifice and dissimulation, he pretended to be willing to enter into a negotiation, hoping thereby to cool their ardour in the field, and to prevent them from driving matters to extremity. James I., ever the dupe of Spanish cunning, contributed not a little, by his foolish intermeddling, to promote the Emperor's schemes. Ferdinand insisted that Frederick, if he would appeal to his clemency, should, first of all, lay down his arms, and James considered this demand extremely reasonable. At his instigation, the Elector dismissed his only real defenders, Count Mansfeld and the Administrator, and in Holland awaited his own fate from the mercy of the Emperor.