Siege of Aachen ( 1614 ) The Siege of Aachen took place in late August , 1614 , when the Spanish Army of Flanders , led by Ambrogio Spinola , 1st Marquis of the Balbases , marched from Maastricht to Germany to support Wolfgang Wilhelm , Count Palatine of Neuburg , during the War of the Jülich Succession . Despite its status as a free imperial city , Aachen was under the protection of John Sigismund of Brandenburg , Neunburg ' s ally , and then rival , in the battle for the United Duchies of Jülich - Cleves - Berg . In 1611 , the Protestant population of Aachen revolted against the Catholic city council , and seized the power . When the Holy Roman Emperor Rudolf II , observing the Peace of Augsburg , ordered the previous state to be restored , the Protestants allied themselves with the Margraviate of Brandenburg . The unexpected arrival of a Spanish army at the gates of the city , however , caused the Protestants to lose courage and surrender Aachen to Spinola . A Catholic garrison was installed and a process of re - Catholicization began . Background . Aachen was a free imperial city of importance from the times of Charlemagne to the 16th century . It was the place of coronation of the King of the Germans until Maximilian II was crowned in Frankfurt in 1562 . Since then , Aachen went into a slow decline . A mainly Catholic city at the time of the Peace of Augsburg , it became religiously divided in the 1560s through the immigration of Protestant refugees from the Netherlands as a consequence of the Spanish persecution during the Dutch revolt . By the 1570s Aachen ' s population numbered 12 , 000 Catholics and 8 , 000 Protestants . The city council and the Emperor tried to exclude the Protestants from political participation in 1581 , but thanks to the economic influence of many of the Protestants citizens , Catholics were forced to allow them to access to the city council . As jurisdiction over Aachen was claimed by the Duke of Jülich and the Bishop of Liege , both of them Catholics , the Catholic population appealed to the first , who complained to Emperor Rudolf II , claiming that his ecclesiastic rights over Aachen had been violated . In 1593 the Reichshofrat declared that the city council could not change the religious status of Aachen , and therefore the Calvinists had to be expelled from the council . When they tried to resist , Rudolf outlawed the city and gave the Archduke Albert , governor of the Spanish Netherlands , the task of enforcing his decision . The subsequent re - Catholicization of the city was conducted by the Archbishop of Cologne . In 1611 , during the War of the Jülich Succession , the Elector of Brandenburg and the Duke of Palatinate - Neuburg , claimants of the Jülich heirdom in opposition to the Catholic Leopold V , Archduke of Austria , organized Protestant religious services in the nearby villages of Stolberg and Weiden . In response , the city council of Aachen imposed a fine on those inhabitants who attended these services . Five citizens were detained for ignoring the town ' s decree and banished as they refused to pay the fine . This caused a riot against the council on 5 July . The Catholic counsellors were expelled and many Catholic building were sacked . The rebels assaulted the church and the college of the Jesuits , smashed the altars and images , and held a mock mass dressed in priestly garments . One priest was injured and 8 others dragged to the city council . A new Protestant council was established and appealed for support to John Sigismund , Elector of Brandenburg , the new Duke of Cleves - Mark . Spanish intervention . Rudolf II ordered the princes of Brandenburg and Palatinate - Neuburg to restore the previous religious and political situation of Aachen under the menace of a ban . The Protestants , however , ignored the command and seriously wounded an Imperial commissary sent to implement the Emperor ' s edict . On May , 1612 , elections were held and Calvinists took the control of the council . In 1613 , as disputes over the Jülich succession continued , one of the claimants , Wolfgang Wilhelm , Count Palatine of Neuburg , converted to Catholicism and gained the support of Spain and of the Catholic League of Germany . On 20 February 1614 , Emperor Matthias II ordered the restoration of the Catholic rule in Aachen , allowing the Spanish Army of Flanders under Ambrogio Spinola to intervene . Fearing an attack , the town council requested some help to the Elector of Brandenburg , who sent several hundred soldiers under general Georg von Pulitz to reinforce the local militia . The city gates were manned and partly walled - up . The Spanish preparations to intervene in the succession dispute alarmed the Dutch Maurice of Nassau , Prince of Orange , who supported John Sigismund of Brandenburg , and knew that the Spanish intervention would destabilize the course of succession . In the middle of June , William Louis , Count of Nassau - Dillenburg warned Prince Maurice that the Spaniards already had 9 , 800 men ready for field service , and that they would soon be joined by a further of 13 , 200 men . With the imminent Spanish threat , Maurice strongly reinforced the garrison of Jülich with 7 infantry companies , and an additional force of 2 , 000 men , for a possible siege . The situation was tense for the two sides . Maurice , with additional troops from towns that were not under serious threat , expected to be able to raise an army of 20 , 000 men , composed of 136 infantry companies and 40 cavalry companies . Meanwhile , Ambrogio Spinola was ready to start the campaign . His first movement was upon Aachen : In August , 1614 , Spinola advanced to Maastricht and its surroundings , and established his camp with an army of 18 , 000 infantry , 2 , 500 cavalry and 11 artillery pieces . From Maastricht , Spinola ' s army entered in the Rhineland accompanied by Guido Bentivoglio , Pope ' s nuncio at Brussels , and two Imperial commissaries . Luis de Velasco , general of the cavalry , opened the way with 600 cavalry , followed by 4 battalions of foot : one of Spaniards , one of Germans and Burgundians and two of Walloons . 600 other horses closed the march . To prevent Aachen from being relieved from Jülich , Spinola detached what remained of his cavalry to block the road between the two cities . The Spanish army appeared before Aachen two hours after its departure from Maastricht . The city lacked of modern fortifications , being surrounded by a single medieval wall . The Spanish troops took a hills which commanded the city , within musket - shot from the walls , and erected a battery to threaten the inhabitants and the 600 - man Brandenburgian garrison . After several days of negotiations , and with little hope of reinforcements , the defenders surrendered Aachen to the Spaniards with great regret of Maurice , that could not be on time for relief . Aftermath . The 600 Brandenburg soldiers were allowed to leave Aachen with their flags and were replaced by 1 , 200 Catholic Germans under the Count of Emden . Although the soldiers of the Spanish army expected loot after several years of truce , Spinola forbade any looting , and the Spanish troops did not enter the town . The Catholic city council was restored , and , on 10 September , issued an edict which gave the Protestant preachers three days to abandon the town , and six weeks for the non - citizen Anabaptists and other foreigners to do the same . From then on , only Catholic schools and schoolmasters were tolerated , heretic books were banned , meat dishes were not allowed to be eaten in inns on the fast days , and a fitting homage was to be paid to the Holy Sacrament and relics when public processions were held . The people who took part in the 1611 rebellion was punished ; in 1616 two ringleaders were executed , more than one hundred citizens who participated in the disturbances were exiled , and others were forced to pay a fine . After the capture of Aachen , Spinola took several towns and castles , including Nuys , Mülheim , and the important German fortress - city of Wesel garrisoned by troops of Brandenburg , causing a great blow to the Protestant forces . Due to strong defense and the large garrison , Spinola decided not to lay siege to Jülich . Then , Prince Maurice marched on Reese with an estimated 18 , 000 men . Spinola subsequently established a position near Xanten , whereupon Spinola and Maurice started negotiations about a neutrality pact , leading to the Treaty of Xanten , which ended the War of the Jülich Succession and all hostilities between Wolfgang Wilhelm , Count Palatine of Neuburg , and John Sigismund , Elector of Brandenburg . The territories of Jülich - Berg and Ravenstein went to Wolfgang Wilhelm of Neuburg , while Cleves - Mark and Ravensberg went to John Sigismund . Spinola refused to give up the key fortress of Wesel , and further negotiations were necessary , but in the end a shaky peace was maintained .