War, was formally declared by the allies against France on the 4th of May, 1702. The principal scenes of its operation were, at first, Flanders, the Upper Rhine, and North Italy. Marlborough headed the allied troops in Flanders during the first two years of the war, and took some towns from the enemy, but nothing decisive occurred. Nor did any actions of importance take place during this period, between the rival armies in Italy. But in the centre of that line from north to south, from the mouth of the Scheldt to the mouth of the Po, along which the war was carried on, the generals of Louis XIV. acquired advantages in 1703, which threatened one chief member of the Grand Alliance with utter destruction. France had obtained the important assistance of Bavaria, as her confederate in the war. The Elector of this powerful German state made himself master of the strong fortress of Ulm, and opened a communication with the French armies on the Upper Rhine. By this junction, the troops of Louis were enabled to assail the Emperor in the very heart of Germany. In the autumn of the year 1703, the combined armies of the Elector and French king completely defeated the Imperialists in Bavaria; and in the following winter they made themselves masters of the important cities of Augsburg and Passau. Meanwhile the French army of the Upper Rhine and Moselle had beaten the allied armies opposed to them, and taken Treves and Landau. At the same time the discontents in Hungary with Austria again broke out into open insurrection, so as to distract the attention, and complete the terror of the Emperor and his council at Vienna.