War was now once more openly declared; some fruitless negotiations having afforded a fair pretext for hostilities.  The rapid appearance of a numerous army under the orders of Don John gave strength to the suspicions of his former dissimulation.  It was currently believed that large bodies of the Spanish troops had remained concealed in the forests of Luxemburg and Lorraine; while several regiments, which had remained in France in the service of the League, immediately re-entered the Netherlands.  Alexander Farnese, prince of Parma, son of the former stadtholderess, came to the aid of his uncle, Don John, at the head of a large force of Italians; and these several reinforcements, with the German auxiliaries still in the country, composed an army of twenty thousand men.  The army of the states-general was still larger; but far inferior in point of discipline.  It was commanded by Antoine de Goignies, a gentleman of Hainault, and an old soldier of the school of Charles V.

After a sharp affair at the village of Riminants, in which the royalists had the worst, the two armies met at Gemblours, on the 31st of January, 1578; and the prince of Parma gained a complete victory, almost with his cavalry only, taking De Goignies prisoner, with the whole of his artillery and baggage.  The account of his victory is almost miraculous.  The royalists, if we are to credit their most minute but not impartial historian, had only one thousand two hundred men engaged; by whom six thousand were put to the sword, with the loss of but twelve men and little more than an hour’s labor.

The news of this battle threw the states into the utmost consternation.  Brussels being considered insecure, the archduke Mathias and his council retired to Antwerp; but the victors did not feel their forces sufficient to justify an attack upon the capital.  They, however, took Louvain, Tirlemont, and several other towns; but these conquests were of little import in comparison with the loss of Amsterdam, which declared openly and unanimously for the patriot cause.  The states-general recovered their courage, and prepared for a new contest.  They sent deputies to the diet of Worms, to ask succor from the princes of the empire.  The count palatine John Casimir repaired to their assistance with a considerable force of Germans and English, all equipped and paid by Queen Elizabeth.  The duke of Alencon, brother of Henry III. of France, hovered on the frontiers of Hainault with a respectable army; and the cause of liberty seemed not quite desperate.

But all the various chiefs had separate interests and opposite views; while the fanatic violence of the people of Ghent sapped the foundations of the pacification to which the town had given its name.  The Walloon provinces, deep-rooted in their attachment to religious bigotry, which they loved still better than political freedom, gradually withdrew from the common cause; and without yet openly becoming reconciled with Spain, they adopted a neutrality which was tantamount to it.  Don John was, however, deprived of all chance of reaping any advantage from these unfortunate dissensions.  He was suddenly taken ill in his camp at Bougy; and died, after a fortnight’s suffering, on the 1st of October, 1578, in the thirty-third year of his age.