The Winter Line was a series of German military fortifications in Italy, constructed during World War II by Organisation Todt. It ran across Italy from just north of where the Garigliano River flows into the Tyrrhenian Sea in the west, through the Apennine Mountains to the mouth of the Sangro River on the Adriatic Sea in the east. The centre of the line, where it crossed the main route north (Highway 6), was based on the mountain Monte Cassino and the old abbey that sat atop it. The line was fortified with gun pits, concrete bunkers, turreted machine-gun emplacements, barbed-wire and minefields. It was the strongest of the German defensive lines south of Rome. The western part of the line, centred around Monte Cassino, was called the Gustav Line, and was protected by the Bernhardt Line a few miles to the south.
Following the Allied invasion of Italy in September 1943, the Italian government had surrendered, but the German Army continued to fight. The Allied armies succeeded in conquering the southern part of Italy, and the Germans retreated to a prepared defensive position called the Winter Line. About 15 German divisions were employed in the defence.
The Allies' immediate objective was the liberation of Rome. The most obvious approach to Rome was the Liri Valley (just north of Monte Cassino), and the Winter Line would prevent the Allies advancing to there.
The German forces were commanded by Field Marshal Albert Kesselring. The defence of the line itself was commanded by General Heinrich von Vietinghoff of the 10th Armee.
The plan called for the US Fifth Army to smash through the line at Monte Cassino and into the Liri Valley. It also called for amphibious landings (Operation Shingle) at Anzio, behind the Gustav Line, so as to bypass it and either draw troops away from the line or make a quick assault on Rome.
In January 1944 the Allied forces began to close on the Gustav Line. The new Supreme Commander, Mediterranean Theatre of Operations was Field Marshal Sir Henry Maitland Wilson who's Headquarters was designated AFHQ, he replaced the American General Dwight Eisenhower who return to the UK to take command of SHAEF. The armies involved were the US Fifth Army, commanded by General Mark W. Clark, consisting of both US and British units, and the British Eighth Army now commanded by General Oliver Leese as General Bernard Montgomery had also been recalled to Britain to prepare for Normandy. The Fifth Army occupied the left (western) flank and the Eighth Army the right.
Throughout January the U.S. 34th Division of the Fifth Army attempted to establish a bridgehead over the Rapido river in the region of Monte Cassino. Generalfeldmarschall Kesselring reinforced the Gustav Line with the 29th and 90th Panzergrenadier divisions (which had been in Rome). Although the Allies managed to cross the Rapido several times, determined counterattacks forced them back each time. They finally succeeded on January 30th, reaching to within a few hundred yards of the monastery walls, but were unable to capture it. On February 12th the exhausted Americans at Monte Cassino were replaced by fresh New Zealand and Indian divisions. These new divisions made further assaults but also suffered heavy casualties and were unable to capture the monastery. Withdrawing these divisions in turn the Allies halted the attacks and spent a month regrouping.
The Allied forces around Anzio came under constant and heavy counterattack by Kesselring, who realised that if he drove the Allies off the beach there he could reinforce the Gustav line. The Allies held their ground, but were unable to advance out of the beachheads. On May 11 the Allies renewed the frontal assault on the Gustav Line, with twelve fresh divisions against the defenders' 6. Progress was made everywhere except around Monte Cassino, and the Free French broke through into the valley of the Austente River. The Germans fell back to their next defensive position, which the Allies rushed to reach before the line could be established. However, General Clark ordered his units to switch their objective to Rome. This ensured its early liberation (on June 5th 1944) and was a major publicity coup, but it allowed Kesselring time to set up his next line of defence, the Gothic Line. Monte Cassino was finally captured on May 18 by the Polish II Corps.
- Map of German defensive lines (http://www.military.com/Resources/ResourceFileView?file=worldwarii_europe_maps_map47.htm)