Siege of Bad Kreuznach The Siege of Bad Kreuznach or the Spanish capture of Bad Kreuznach took place on 9 September 1620 , in Kreuznach , Electorate of the Palatinate , between the Spanish forces of Don Ambrosio Spinola , commanded by Don Carlos Coloma de Saa , 1st Marquess of Espinar against the forces of the Electoral Palatinate during the Palatinate campaign , in the context of the Thirty Years ' War . The Spanish troops stormed the city and obtained the surrender of the garrison . Later the town was released on a promise not to fight back against the Holy Roman Empire . < ref name = " Polišenský / Snider " > Polišenský / Snider . " War and society in Europe ( 1618 - 1648 ) " < / ref > Background . The Thirty Years ' War began in 1618 with the Bohemian Revolt , when the authorities of this kingdom offered their throne to the Protestant Frederick V of the Palatinate , who accepted , initiating a conflict between the Protestant Union led by Frederick and the House of Habsburg . Two years after the outbreak of the war the situation had apparently stalled , but in reality the Habsburgs through its diplomatic maneuvers were able to isolate politically to Frederick , between whose hits highlighted Spain ' s entry into the conflict . Under the agreement with the Emperor , in August 1620 , Don Ambrosio Spinola , commander of the Spanish army , crossed the Rhine at the head of an army of 22 , 000 men and invaded the Lower Palatinate . Since the Elector Palatine had not yet begun hostilities against the Spanish Monarchy , Spinola decided to proceed to occupy , peacefully if was possible , the main towns of his state . On 8 September Spinola marched with his army against the Palatine forces not far from Oppenheim . At midnight ordered to his Field Master Don Carlos Coloma , Governor of Cambrai , taking the town of Kreuznach , in command of two Tercios of infantry , numbering about 5 , 000 soldiers and 300 horsemen , a town of some importance because had a bridge over the Rhine protected by walls on both sides of the river and a castle . Assault . Don Carlos Coloma arrived with his troops at the gates of the town on the evening , 10 September , and sent emissaries to the authorities saying that if they surrendered to the obedience of Emperor Ferdinand II would be well treated . Faced with an ambiguous response from the defenders , Coloma ordered to place the 4 cannon s he had , and moved his troops to the foot of the walls , and the gate of the town to launch the assault . The defenders of Kreuznach , whose forces consisted of three companies of infantry and one of cavalry , decided to act and fired their muskets from the castle overlooking the town . Then , the Spanish , in perfect formation , responded by opening fire with their cannons . Few minutes after , the garrison decided to surrender the town . The Spanish troops captured the horses and the weapons of the Palatine soldiers , and Coloma forced the Palatine troops to take an oath not to fight anymore against the Emperor . Consequences . With the news of the fell of Kreuznach , Spinola continued the march with his army over the Palatinate to Alsheim , one of the main city of the region , and captured it in the same day . Four days after , on 14 September , Spinola , with a great maneuver of distraction over Worms , captured Oppenheim , without too much difficulty , causing a severe blow to the Protestant forces .