During the forty days which had elapsed since the battle of Essling, the Archduke Charles had limited his efforts to fortifying his positions on the left bank of the Danube, without attempting any offensive operations against Napoleon, and had in vain waited for the reinforcements that his brothers, and the generals dispersed over the Austrian territory, were to bring him. The skilful generals of Napoleon had everywhere intercepted their communications. However, 130,000 or 140,000 of the enemy prepared to dispute with us the passage of the Danube. One hundred and fifty thousand French were assembled around Vienna; Massena had not quitted the island of Lobau; Napoleon established himself there with his staff on the 1st July. Skilful and learned in the theory of war, the Archduke Charles felt his inferiority in face of the unexpected genius of the Emperor Napoleon. He had carefully fortified Aspern, Essling, Ensdorf, but he had not foreseen that the place of disembarkation, and the point of attack, would be changed. The heights which ranged from Neusiedel to Wagram, well occupied by excellent troops, were not furnished with redoubts; it was, however, these same heights the conqueror was about to attack. The bridges which united the right bank to the island of Lobau were at present out of danger from all inundations and accidents. New and ingenious inventions had utilized all the resources drawn from the magazines of Vienna and the vast forests of Austria. A stockade protected the roadway, and flying bridges of an extraordinary size and solidity could be thrown in several hours over the small arm of the stream which separated the island of Lobau from the left bank. Two days previously the archduke had quitted the heights to approach the banks of the Danube, waiting uselessly for the attack of the enemy; on the 3rd July he drew back his forces towards the hills. The columns of the French continued to defile over the great bridge, and massed themselves little by little on the island. The cannon-balls of the enemy began to rain on the shores of Lobau, but the space was too vast to permit the Austrian batteries to sweep the interior. During the night of the 4th the first bridges were thrown over the small arm of the Danube between the island and the mainland; flat-bottomed boats brought over soldiers without interruption, and these moored the boats and fixed the plankings. The enemy's fire had become incessant and deadly. The engineers continued their work without appearing to perceive the danger which threatened them, any more than the thunder which rolled over their heads, the lightning which flashed through the darkness, or the rain, which did not cease to fall in torrents. The batteries of the island of Lobau were at length unmasked, everywhere furnished with guns of the largest calibre, and the fire was directed towards the little town of Enzensdorf; after that the Archduke Charles could not deceive himself as to the menaced point.