Wellesley moved against Soult at Oporto, and, by a dextrous crossing of that river in his rear, compelled him to beat a calamitous retreat on Spain, with the loss of all his cannon and stores.

The French reached Lugo an armed rabble, and were greeted there with jeers and execrations by the men of Ney's corps.

The two Marshals themselves took up the quarrel, and so fierce were the taunts of Ney that Soult drew his sword and a duel was barely averted.[212] An appearance of concord was restored during their operations in Galicia and Asturias: but no opportunity was missed of secretly thwarting the hated rival; and here, as all through the Peninsular War, the private jealousies of the French leaders fatally compromised the success of their arms.
Wellesley, seeing that the operations in Galicia would never decide the war, began to prepare a deadly blow at the centre of French authority, Madrid.
While Wellesley thrust a thin wedge into the heart of Spain, the Archduke Charles was overthrown on the banks of the Danube.

After drawing in reinforcements from France, the Rhenish Confederation, and Eugene's army of Italy, the French Emperor disposed of 180,000 highly-trained troops, whom he massed in the Lobau Island, or on the right shore of the Danube.

Every preparation was made for deceiving the Austrians as to the point of crossing and with complete success.
With great labour the defenders threw up intrenchments facing the north side of the island.