The taking of Rhinefeldt, Roeteln, and Fribourg, was the immediate consequence of the duke's victory. His army now increased by considerable recruits, and his projects expanded in proportion as fortune favoured him. The fortress of Breysach upon the Rhine was looked upon as holding the command of that river, and as the key of Alsace. No place in this quarter was of more importance to the Emperor, and upon none had more care been bestowed. To protect Breysach, was the principal destination of the Italian army, under the Duke of Feria; the strength of its works, and its natural defences, bade defiance to assault, while the Imperial generals who commanded in that quarter had orders to retain it at any cost. But the duke, trusting to his good fortune, resolved to attempt the siege. Its strength rendered it impregnable; it could, therefore, only be starved into a surrender; and this was facilitated by the carelessness of the commandant, who, expecting no attack, had been selling off his stores. As under these circumstances the town could not long hold out, it must be immediately relieved or victualled. Accordingly, the Imperial General Goetz rapidly advanced at the head of 12,000 men, accompanied by 3000 waggons loaded with provisions, which he intended to throw into the place. But he was attacked with such vigour by Duke Bernard at Witteweyer, that he lost his whole force, except 3000 men, together with the entire transport. A similar fate at Ochsenfeld, near Thann, overtook the Duke of Lorraine, who, with 5000 or 6000 men, advanced to relieve the fortress. After a third attempt of general Goetz for the relief of Breysach had proved ineffectual, the fortress, reduced to the greatest extremity by famine, surrendered, after a blockade of four months, on the 17th December 1638, to its equally persevering and humane conqueror.