Spinola, after hovering for a few days in the neighbourhood, descended upon the Imperial city of Aachen (Aix-la-Chapelle).  This had been one of the earliest towns in Germany to embrace the Reformed religion, and up to the close of the sixteenth century the control of the magistracy had been in the hands of the votaries of that creed.  Subsequently the Catholics had contrived to acquire and keep the municipal ascendency, secretly supported by Archduke Albert, and much oppressing the Protestants with imprisonments, fines, and banishment, until a new revolution which had occurred in the year 1610, and which aroused the wrath of Spinola.  Certainly, according to the ideas of that day, it did not seem unnatural in a city where a very large majority of the population were Protestants that Protestants should have a majority in the town council.  It seemed, however, to those who surrounded the Archduke an outrage which could no longer be tolerated, especially as a garrison of 600 Germans, supposed to have formed part of the States’ army, had recently been introduced into the town.  Aachen, lying mostly on an extended plain, had but very slight fortifications, and it was commanded by a neighbouring range of hills.  It had no garrison but the 600 Germans.  Spinola placed a battery or two on the hills, and within three days the town surrendered.  The inhabitants expected a scene of carnage and pillage, but not a life was lost.  No injury whatever was inflicted on person or property, according to the strict injunctions of the Archduke.  The 600 Germans were driven out, and 1200 other Germans then serving under Catholic banners were put in their places to protect the Catholic minority, to whose keeping the municipal government was now confided.

Spinola, then entering the territory of Cleve, took session of Orsoy, an important place on the Rhine, besides Duren, Duisburg, Kaster, Greevenbroek and Berchem.  Leaving garrisons in these places, he razed the fortifications of Mulheim, much to the joy of the Archbishop and his faithful subjects of Cologne, then crossed the Rhine at Rheinberg, and swooped down upon Wesel.  This flourishing and prosperous city had formerly belonged to the Duchy of Cleve.  Placed at the junction of the Rhine and Lippe and commanding both rivers, it had become both powerful and Protestant, and had set itself up as a free Imperial city, recognising its dukes no longer as sovereigns, but only as protectors.  So fervent was it in the practice of the Reformed religion that it was called the Rhenish Geneva, the cradle of German Calvinism.  So important was its preservation considered to the cause of Protestantism that the States-General had urged its authorities to accept from them a garrison.  They refused.  Had they complied, the city would have been saved, because it was the rule in this extraordinary campaign that the belligerents made war not upon each other, nor in each others territory, but against neutrals and upon neutral soil.  The Catholic forces under Spinola or his lieutenants, meeting occasionally and accidentally with the Protestants under Maurice or his generals, exchanged no cannon shots or buffets, but only acts of courtesy; falling away each before the other, and each ceding to the other with extreme politeness the possession of towns which one had preceded the other in besieging.