where did the decisive early encounters of the civil war take place
Siege
In the 1530s and ' 40s , the new style of fortification began to spread out of Italy into the rest of Europe , particularly to France , the Netherlands , and Spain . Italian engineers were in enormous demand throughout Europe , especially in war - torn areas such as the Netherlands , which became dotted by towns encircled in modern fortifications . The densely populated areas of Northern Italy and the United Provinces ( the Netherlands ) were infamous for their high degree of fortification of cities . It made campaigns in these areas very hard to successfully conduct , considering even minor cities had to be captured by siege within the span of the campaigning season . In the Dutch case , the possibility of flooding large parts of the land provided an additional obstacle to besiegers , for example at the Siege of Leiden . For many years , defensive and offensive tactics were well balanced , leading to protracted and costly wars such as Europe had never known , involving more and more planning and government involvement . The new fortresses ensured that war rarely extended beyond a series of sieges . Because the new fortresses could easily hold 10,000 men , an attacking army could not ignore a powerfully fortified position without serious risk of counterattack . As a result , virtually all towns had to be taken , and that was usually a long , drawn - out affair , potentially lasting from several months to years , while the members of the town were starved to death . Most battles in this period were between besieging armies and relief columns sent to rescue the besieged .
In the 1530s and ' 40s , the new style of fortification began to spread out of Italy into the rest of Europe , particularly to France , the Netherlands , and Spain . Italian engineers were in enormous demand throughout Europe , especially in war - torn areas such as the Netherlands , which became dotted by towns encircled in modern fortifications . The densely populated areas of Northern Italy and the United Provinces ( the Netherlands ) were infamous for their high degree of fortification of cities . It made campaigns in these areas very hard to successfully conduct , considering even minor cities had to be captured by siege within the span of the campaigning season . In the Dutch case , the possibility of flooding large parts of the land provided an additional obstacle to besiegers , for example at the Siege of Leiden . For many years , defensive and offensive tactics were well balanced , leading to protracted and costly wars such as Europe had never known , involving more and more planning and government involvement . The new fortresses ensured that war rarely extended beyond a series of sieges . Because the new fortresses could easily hold 10,000 men , an attacking army could not ignore a powerfully fortified position without serious risk of counterattack . As a result , virtually all towns had to be taken , and that was usually a long , drawn - out affair , potentially lasting from several months to years , while the members of the town were starved to death . Most battles in this period were between besieging armies and relief columns sent to rescue the besieged .