In 1623 Mansfeld issued from his Frisian stronghold, and the threat of a visitation from his army induced the princes of the Lower Saxon Circle to join him. Christian was himself a member of the Circle, and although he resigned his bishopric, he was taken, with many of his men, into the service of his brother, the duke of Brunswick-Wolfenbüttel; around the mercenary nucleus gathered many thousands of volunteers, and the towns and the nobles' castles alike were alarmed at the progress of the Catholics, who were reclaiming Protestant bishoprics. But this movement was nipped in the bud by the misconduct of the mercenaries. The authorities of the Circle ordered Christian to depart. He returned to Holland, therefore, but Tilly started in pursuit and caught him at Stadtlohn, where on 28 July/6 August 1623 his army was almost destroyed. Thereupon the Lower Saxon Circle, which, like the Bohemians, had ordered collectively taxes and levies of troops that the members individually furnished cither not at all or unwillingly, disbanded their army to prevent brigandage. Mansfeld, too, having eaten up East Friesland, returned to Holland in 1624.
The only material factor was now Tilly's ever-victorious Army of the League, but for the present it was suspended inactive in the midst of a spider's web of European and German diplomacy. Spain and England had lotcr- quarrcllcd. The latter became the ally of France, over whose policy Richelieu now ruled, and the United Provinces and (later) Denmark joined them. Thus the war was extended beyond the borders of the Empire, and the way opened for ceaseless foreign interventions. From the battle of Stadtlohn to the pitiful end twenty years later, the decision of German quarrels lay in the hands of foreign powers, and for two centuries after the treaty of Westphalia the evil tradition was faithfully followed.