Less apprehensive of open enemies, than of the jealousy of the friendly powers, he left Upper Germany, which he had secured by conquests and alliances, and set out in person to prevent a total defection of the Lower German states, or, what would have been almost equally ruinous to Sweden, a private alliance among themselves. Offended at the boldness with which the chancellor assumed the direction of affairs, and inwardly exasperated at the thought of being dictated to by a Swedish nobleman, the Elector of Saxony again meditated a dangerous separation from Sweden; and the only question in his mind was, whether he should make full terms with the Emperor, or place himself at the head of the Protestants and form a third party in Germany. Similar ideas were cherished by Duke Ulric of Brunswick, who, indeed, showed them openly enough by forbidding the Swedes from recruiting within his dominions, and inviting the Lower Saxon states to Luneburg, for the purpose of forming a confederacy among themselves. The Elector of Brandenburg, jealous of the influence which Saxony was likely to attain in Lower Germany, alone manifested any zeal for the interests of the Swedish throne, which, in thought, he already destined for his son. At the court of Saxony, Oxenstiern was no doubt honourably received; but, notwithstanding the personal efforts of the Elector of Brandenburg, empty promises of continued friendship were all which he could obtain. With the Duke of Brunswick he was more successful, for with him he ventured to assume a bolder tone. Sweden was at the time in possession of the See of Magdeburg, the bishop of which had the power of assembling the Lower Saxon circle. The chancellor now asserted the rights of the crown, and by this spirited proceeding, put a stop for the present to this dangerous assembly designed by the duke. The main object, however, of his present journey and of his future endeavours, a general confederacy of the Protestants, miscarried entirely, and he was obliged to content himself with some unsteady alliances in the Saxon circles, and with the weaker assistance of Upper Germany.