Notwithstanding the strictness by which Philip had tied his great general’s hands, Farnese felt the urgency of the situation.  By the end of June, accordingly, although full of his measures for marching to the relief of the Leaguers in Normandy, he moved into Gelderland, coming by way of Xanten, Rees, and neighbouring places.  Here he paused for a moment perplexed, doubting whether to take the aggressive in Gelderland or to march straight to the relief of Groningen.  He decided that it was better for the moment to protect the line of the Waal.  Shipping his army accordingly into the Batavian Island or Good-meadow (Bet-uwe), which lies between the two great horns of the Rhine, he laid siege to Fort Knodsenburg, which Maurice had built the year before, on the right bank of the Waal for the purpose of attacking Nymegen.  Farnese, knowing that the general of the States was occupied with his whole army far away to the north, and separated from him by two great rivers, wide and deep, and by the whole breadth of that dangerous district called the Foul-meadow (Vel-uwe), and by the vast quagmire known as the Rouvenian morass, which no artillery nor even any organised forces had ever traversed since the beginning of the world, had felt no hesitation in throwing his army in boats across the Waal.  He had no doubt of reducing a not very powerful fortress long before relief could be brought to it, and at the same time of disturbing by his presence in Batavia the combinations of his young antagonist in Friesland and Groningen.

So with six thousand foot and one thousand horse, Alexander came before Knodsenburg.  The news reached Maurice at Steenwyk on the 15th July.  Instantly changing his plans, the prince decided that Farnese must be faced at once, and, if possible, driven from the ground, thinking it more important to maintain, by concentration, that which had already been gained, than to weaken and diffuse his forces in insufficient attempts to acquire more.  Before two days had passed, he was on the march southward, having left Lewis William with a sufficient force to threaten Groningen.  Coming by way of Hasselt Zwol to Deventer, he crossed the Yssel on a bridge of boats on the 18th of July, 1591 and proceeded to Arnhem.  His army, although excessively fatigued by forced marches in very hot weather, over nearly impassable roads, was full of courage and cheerfulness, having learned implicit confidence in their commander.  On the 20th he was at Arnhem.  On the 22nd his bridge of boats was made, and he had thrown his little army across the Rhine into Batavia, and entrenched himself with his six thousand foot and fourteen hundred horse in the immediate neighbourhood of Farnese—­Foul-meadow and Good-meadow, dyke, bog, wold, and quagmire, had been successfully traversed, and within one week of his learning that the great viceroy of Philip had reached the Batavian island, Maurice stood confronting that famous chieftain in battle-array.

On the 22nd July, Farnese, after firing two hundred and eighty-five shots at Fort Knodsenburg, ordered an assault, expecting that so trifling a work could hardly withstand a determined onslaught by his veterans.  To his surprise they were so warmly received that two hundred of the assailants fell at the first onset, and the attack was most conclusively repulsed.