Under cover of this feigned attack, Farnese arrived at the river side on the 15th September, seized an open village directly opposite Lagny, which was connected with it by a stone bridge, and planted a battery of nine pieces of heavy artillery directly opposite the town.  Lagny was fortified in the old-fashioned manner, with not very thick walls, and without a terreplain.  Its position, however, and its command of the bridge, seemed to render an assault impossible, and De la Fin, who lay there with a garrison of twelve hundred French, had no fear for the security of the place.  But Farnese, with the precision and celerity which characterized his movements on special occasions, had thrown pontoon bridges across the river three miles above, and sent a considerable force of Spanish and Walloon infantry to the other side.  These troops were ordered to hold themselves ready for an assault, so soon as the batteries opposite should effect a practicable breach.  The next day Henry, reconnoitering the scene, saw, with intense indignation, that he had been completely out-generalled.  Lagny, the key to the Marne, by holding which he had closed the door on nearly all the food supplies for Paris, was about to be wrested from him.  What should he do?  Should he throw himself across the river and rescue the place before it fell?  This was not to be thought of even by the audacious Bearnese.  In the attempt to cross the river, under the enemy’s fire, he was likely to lose a large portion of his army.  Should he fling himself upon Renty’s division which had so ostentatiously offered battle the day before?  This at least might be attempted, although not so advantageously as would have been the case on the previous afternoon.  To undertake this was the result of a rapid council of generals.  It was too late.  Renty held the hills so firmly entrenched and fortified that it was an idle hope to carry them by assault.  He might hurl column after column against those heights, and pass the day in seeing his men mowed to the earth without result.

His soldiers, magnificent in the open field, could not be relied upon to carry so strong a position by sudden storm; and there was no time to be lost.  He felt the enemy a little.  There was some small skirmishing, and while it was going on, Farnese opened a tremendous fire across the river upon Lagny.  The weak walls soon crumbled; a breach was effected, the signal for assault was given, and the troops posted on the other side, after a brief but sanguinary straggle, overcame all, resistance, and were masters of the town.  The whole garrison, twelve hundred strong, was butchered, and the city thoroughly sacked; for Farnese had been brought up in the old-fashioned school of Alva; and Julian Romero and Com-. wander Requesens.