XII Corps ( United States ) The XII Corps fought from northern France to Austria in World War II . Constituted in the Organized Reserves in 1933 , it was activated on 29 August 1942 at Columbia , South Carolina . XII Corps became operational in France as part of Lieutenant General George S . Patton ' s Third Army on 1 August 1944 . Initially commanded by Major General Gilbert R . Cook , bad health forced MG Cook to relinquish command to Major General Manton S . Eddy within three weeks . MG Eddy commanded the corps until late April 1945 , when his own health problems forced him to turn over command to MG Stafford LeRoy Irwin . Pursuit across northern France . Assembling south of Le Mans on 13 August 1944 , XII Corps began driving eastward and liberated the cities of Orléans and Châteaudun within five days . Moving rapidly against disorganized German resistance , the corps rapidly took Sens , Montargis , Troyes , Châlons - sur - Marne , and Vitry - le - François . By 31 August 1944 , XII Corps had seized a bridgehead over the Meuse River at Commercy in Lorraine . Lorraine . At the beginning of September 1944 , serious gasoline shortages forced an abrupt halt to General Patton ' s pursuit across northern France . Resuming its advance on 4 September , but facing shortages of gasoline and ammunition because of the allied logistical crisis , XII Corps now confronted a vastly changed tactical situation . A combination of German reinforcements and regained cohesion in the German forces ( Fifth Panzer Army ) confronting the U . S . Third Army resulted in dramatically increased German resistance in the region of Metz and Nancy in the Moselle River valley . From the German point of view , Lorraine ( German : " Lothringen " ) was seen as part of Germany and would be defended with bitter determination . Across the Moselle . XII Corps assaulted across the Moselle River at Dieulouard on 13 September 1944 , and heavy fighting ensued for three days as the Germans attempted to collapse the bridgehead . During 15 – 16 September , the corps liberated Nancy and Lunéville . The advance of XII Corps was met by an armored counterattack of the Fifth Panzer Army . At Arracourt during 19 – 20 September 1944 , the corps ' U . S . 4th Armored Division destroyed two German Panzer brigades . Desperate fighting continued until 1 October 1944 for the area around Arracourt , Moyenvic , and Grémecey ' s forest . Resuming its advance , the corps pushed to the river Seille by 9 October 1944 . To the Saar . After resting and reorganizing for a month , XII Corps opened an offensive to reach the Saar River on 8 November 1944 . Château - Salins was taken on 9 November , and the corps battled through firm German resistance to liberate Faulquemont on 20 November 1944 . On 24 November , the corps crossed the Sarre River and then liberated Saint - Avold on 27 November 1944 . From 1 to 11 December 1944 , XII Corps fought for , and liberated the towns of Sarre - Union and Sarreguemines . On 12 December , the corps entered Germany and began operations against the Siegfried Line fortifications . Ardennes . Germany ' s surprise offensive into the Ardennes on 16 December 1944 , resulted in the U . S . Third Army being moved northward to attack the southern flank of the German army in Belgium and Luxembourg . Turning over its part of the front to the U . S . XV Corps , XII Corps moved to the area of Luxembourg city on 21 December 1944 . Subsequently , the corps cleared the west bank of the Moselle River in Luxembourg until 11 January 1945 . During 18 – 23 January , XII Corps assaulted across the Sauer River and cleared the twin confluences of the Our River and the Sauer , and then that of the Sauer and Moselle Rivers . Into Germany . On 7 February 1945 , the corps assaulted across the Our and Sauer Rivers between Vianden and Echternach , repelling German counter - attacks against the bridgeheads and gradually clearing Siegfried Line bunkers in the area until 15 February . On 18 February 1945 , XII Corps drove on the Prüm River , which it assaulted across on the night of 24 – 25 February . Bitburg fell to XII Corps on 28 February 1945 . The corps assaulted across the Kyll River on the night of 2 – 3 March 1945 , and reached the Rhine River in the area of Andernach on 7 March . From 7 – 11 March 1945 , the corps mopped up along the west bank of the Rhine and Moselle Rivers . Across the Rhine . Assaulting across the Moselle River at Treis on 14 March 1945 , the corps seized Bad Kreuznach on 18 March and Worms on 21 March . On 22 March 1945 , XII Corps assaulted across the Rhine River at Oppenheim without involved preparation and caught the Germans in the area off - guard . From 21 – 27 March , the corps battled for , and seized Mainz . On 25 March , Darmstadt fell to XII Corps . Against the wishes of MG Eddy , General Patton ordered the XII Corps to dispatch a raiding force ( Task Force Baum ) to liberate the Hammelburg prisoner of war camp on 25 March . TF Baum was trapped and destroyed near Hammelburg on 27 March 1945 . On 26 March 1945 , the corps assaulted across the Main River into Frankfurt am Main , and fought for three days to capture the city in the face of German resistance characterized by the use of assault guns and a heavy concentration of Flak artillery in the dense urban environment . Moving rapidly northeast , the corps bypassed German troop concentrations and conquered Hanau ( 28 March ) , Bad Hersfeld ( 31 March ) , and Fulda ( 2 April ) . The corps paused between Gotha and Suhl on 3 April 1945 . On 4 April 1945 XII Corps troops discovered a Nazi stash of art treasures and gold in a salt mine at Merkers , and then took Meiningen the following day . A curious decision . In a questionable allocation of allied military strength , Generals Dwight D . Eisenhower ( supreme allied commander ) and Omar N . Bradley ( commander of U . S . 12th Army Group ) paused 12th Army Group ' s ( to which the U . S . Third Army belonged ) advance at the Elbe River and then committed the U . S . Third Army , the U . S . Seventh Army and the French First Army to overrun what they believed was an " Alpine Redoubt " in the south of Germany . The so - called redoubt proved to be a myth and the commitment of eight U . S . and French army corps against it was a curious use of allied military resources while other allied armies in the north paused for weeks only 80 miles from the true heart of German resistance , Berlin . Final operations . This decision committed XII Corps to an advance to the southeast . Taking Coburg on 11 April 1945 , the corps then took Bayreuth in a three - day battle ending on 16 April . Moving rapidly , XII Corps liberated the Flossenburg concentration camp on 23 April and reached the Danube River on 25 April 1945 . Operating simultaneously in Germany and Czechoslovakia , the corps crossed into Austria and assaulted across the Danube River southwest of Regensburg on 26 April 1945 . The corps seized Linz on 4 – 5 May 1945 , and began clearing passes in Czechoslovakia for a drive on Prague . VE Day brought a close to combat operations for the XII Corps , as the corps linked up with Red Army troops near Amstetten . Campaign credits and inactivation . XII Corps is credited with service in the Northern France , Rhineland , Ardennes - Alsace , and Central Europe campaigns . Headquarters , XII Corps , was inactivated on 15 December 1945 in Germany . The corps was subsequently activated and inactivated several times , with the last inactivation occurring on 1 April 1968 at Atlanta , Georgia .