War (1618�1648). Harsh Spanish occupation in 1621�1632 ended when Protestant Swedish armies liberated the area. In 1635, however, the ruthless Croatian troops of the Austrian emperor's army entered Kaiserslautern and killed 3,000 of the 3,200 residents in three days' plundering. Landstuhl was saved from a similar fate by surrendering without a fight. It took Kaiserslautern about 160 years to repopulate itself.
Conflict did not end with the Peace of Westphalia in 1648. The Elector of the Pfalz had difficulty with many of his subjects and ordered all castles, including Nanstein, destroyed. The French repeatedly invaded and occupied the area, residing in Kaiserslautern in 1686�1697. Nevertheless, after the treaty of Utrecht it was restored to be part of the Palatinate. During the unquiet episodes in the 18th century, the Palatinate was the scene of fighting between French and German troops of different states. In 1713, the French destroyed Barbarossa's castle and the city's wall towers. From 1793 until Napoleon's defeat at Waterloo in 1815, the area was under French administration.
As French power declined after 1815, Kaiserslautern and the Palatinate became a Bavarian province and remained so until 1918. After World War I, French troops again occupied the Palatinate for several years.
In World War II, more than 60% of Kaiserslautern was destroyed by bombs from Allied aircraft. The railway and several main roads were primary targets. The heaviest attacks occurred on 7 January, 11 August, and 28 September 1944. Of the 20,000 homes, 11,000 were destroyed or damaged. The cemetery wall opposite Kleber Kaserne still bears shell marks of these raids. Unexploded ordnance from WWII continues to be discovered in and around Kaiserslautern. In May 2012 an unexploded 250-pound Allied bomb was found, buried deeply and reportedly covered by water pipe, during a construction project in the downtown area of the city.
