The Austrians had crossed the Isar in good order, Charles himself at Landshut. If they had kept directly onward they might have still wedged themselves between Davout and Lefebvre. But the Archduke grew timid at the prospect of swamps and wooded hills before him; uncertain of his enemy's exact position, he threw forward three separate columns by as many different roads, and thus lengthened his line enormously, the right wing being at Essenbach, the center advanced before Landshut to Hohen-Thann, the left at Morsbach. At four in the morning of the eighteenth Lefebvre received orders to fall on the Austrian left, while flying messengers followed each other in quick succession to spur on Massena with urgent pleas of immediate necessity. It was hoped that he might come up to join an attack which, though intended mainly to divert the Austrians from Davout, could by his help be turned into an important victory. The Archduke during the day collected sixty-six thousand men at Rohr for his onset, and thirty-five thousand men at Ludmannsdorf to cover his flank, leaving twenty-five thousand at Moosburg. That night Davout's last corps, that of Friant, came in, and he began his march. Massena, who had collected his army and was coming from Augsburg, was ordered to turn, either left toward Abensberg, in order to join Davout, or right toward Landshut, to attack Charles's rear, as circumstances should determine. Lefebvre was now commanded to assume the defensive and await events at Abensberg. Throughout the morning of the nineteenth Davout and Charles continued their march, drawing ever closer to each other. At eleven the French van and the Austrian left collided. The latter made a firm stand, but were driven in with great slaughter. A considerable force which had been sent to strike Davout on the flank at Abensberg was also defeated by Lefebvre. Before evening the entire French army was united and in hand. Davout was on the left toward the river Laber, Lefebvre, with the Bavarians and several French divisions, was in the center beyond the river Aben, while Massena had reached a point beyond Moosburg. Within sixty hours Napoleon had conceived and completed three separate strategic movements: the withdrawal of the whole army toward Ingolstadt, the advance of his right to strengthen the incoming left, and the rearrangement of his entire line with the right on his enemy's base of operations.