▁through ▁Elect or ▁Frederick ▁II . ▁ ▁The ▁Th irty ▁Years ' ▁War ▁broke ▁out ▁in ▁ 1 6 1 8 ▁from ▁the ▁struggle ▁between ▁the ▁C athol ics ▁and ▁the ▁Protest ants ▁and ▁the ▁political ▁t ensions ▁in ▁the ▁German ▁Empire . ▁France , ▁Spain ▁and ▁Sweden ▁interven ed . ▁ ▁When ▁peace ▁was ▁established ▁in ▁ 1 6 4 8 , ▁the ▁country ▁was ▁econom ically ▁ru ined ▁with ▁and ▁half ▁the ▁population ▁having ▁died ▁from ▁the ▁fighting , ▁disease ▁or ▁fam ine . ▁ ▁During ▁the ▁ 1 7 th ▁century , ▁the ▁Middle ▁Rh ine ▁was ▁increasing ly ▁the ▁scene ▁of ▁a ▁long - last ing ▁conflict ▁between ▁Germany ▁and ▁France . ▁ ▁After ▁dev ast ation ▁of ▁the ▁Th irty ▁Years ' ▁War , ▁the ▁War ▁of ▁the ▁Pal at ine ▁Su cc ession ▁brought ▁in ▁ 1 6 8 8 – 1 6 9 2 ▁further ▁destruction ▁of ▁cast les ▁and ▁fort ifications ▁part ▁of ▁the ▁cities ' ▁def enses . ▁ ▁The ▁city ▁of ▁Kob len z ▁was ▁re construct ed ▁in ▁the ▁ 1 8 th ▁century ▁and ▁is ▁character ized ▁by ▁the ▁style ▁of ▁early ▁classic ism . ▁ ▁After ▁the ▁French ▁Revolution ary ▁Wars , ▁the ▁left ▁bank ▁of ▁the ▁Rh ine ▁was ▁an nex ed ▁by ▁the ▁French ▁Republic ▁and ▁later ▁the ▁French ▁Empire . ▁ ▁Pref ect ▁Le z ay - M arn és ia , ▁who ▁res ided ▁in ▁Kob len z ▁began ▁rest oring ▁the ▁road ▁on ▁the ▁left