In an attempt to delay the Allied advance toward Rome, Italy, German forces set up a series of defensive lines, collectively called the Winter Line, that began with the southern-most Volturno Line to the northern-most Rome Switch Line, with the Gustav Line intending to be the strongest. The Winter Line was mainly constructed by members of the German Organization Todt, featuring many gun pits, concrete bunkers, machine gun nests, minefields, and other defensive structures, manned by troops of 15 German divisions.
In the first week of Oct 1943, British infantry crossed the Biferno River on the Adriatic Sea coast of Italy, reaching the eastern end of the southern-most Volturno Line, also known as Viktor Line; a German armor counterattack on 4 Oct nearly pushed the infantrymen back across the river, but British engineers were able to set up a bridge in time to bring up Canadian and British tanks to the front to counter the German counterattack. By 6 Oct, the territory lost to the German counterattack was regained, and the British and Canadian troops would gradually push north toward the Barbara Line. On the western end of the Volturno Line, the US 5th Army crossed the Volturno River during the night of 12 Oct and advanced through a series of delay action engagements.
The next defensive line, Barbara Line, was reached by Allies on 2 Nov, near-simultaneously on the Tyrrhenian Sea coast by US 5th Army and on the Adriatic Sea coast by British 8th Army. In early Dec, on the western side, German troops fell back to the intermediate Bernhardt Line, also known as Reinhard Line, while on the eastern side the Germans fell back to the main Gustav Line.
The US 5th Army attacked the Bernhardt Line on 1 Dec 1943, using both US and British troops; Monte Camino and the surroundings were captured after eight days of heavy combat. On 10 Dec, US troops captured the peaks surrounding the Mignano Gap; despite gaining the advantageous terrain, the Americans could not drive the Germans out of the valley until 16 Dec, and fighting in this general area would last until the end of the year.
The British 8th Army attack on the Gustav Line began on 28 Nov 1943, one week behind schedule due to heavy rains. On 5 Dec, Canadian 1st Infantry Division under Major-General Christopher Vokes launched an attack at the German defenses along the Moro River; meanwhile, New Zealand 2nd Division marched toward Orsogna. Although the advance across the lines south of the Gustav Line had been costly in terms of casualties, the movement had been relatively swift, and the Allied leadership expected the same from the British 8th Army at the Gustav Line. As Route 5, the main highway linking Pescara on the east coast with Rome to the west was situated less than 30 miles from the Gustav Line, several German divisions, including the tough 1st Parachute Division and 5th Mountain Division, were prepared the stand their ground. At 0000 hours on 5 Dec, Canadian troops attacked toward Villa Rogatti, immediately engaging in heavy fighting, but were able to capture the town before dawn; the mid-morning counterattack by German tanks was repulsed, but the Canadians suffered high casualties and had to abandon Villa Rogatti. A similar scene played out at San Leonardo and San Donato on the following day. In the afternoon of 8 Dec, a renewed attack was launched at San Leonardo after a two-hour artillery bombardment, finally securing a bridgehead by sundown; overnight, troops of Royal Canadian Engineers built a bridge over the Moro River to allow tanks and supply trucks to reinforce the bridgehead. San Leonardo was captured by mid-morning on 9 Dec, and remaining German forces, after holding out in positions surrounding the town for the length of the day, fell back northward about 3 miles toward the area later to be nicknamed “The Gully”.
Meanwhile, New Zealand troops attacked Orsogna starting on 7 Dec, with British paratroopers in support; this attack would fail to dislodge German defenders and would be called off on the following day.
Three Canadian battalions attacked “The Gully” on 10 Dec, capturing Vino Ridge, but over the next three days, they would suffer heavy casualties against stubborn defense by troops of German 90th Panzergrenadier Division. On 13 Dec, however, German strength began to be dwindling, and German 1st Parachute Division was moved up to relieve 90th Panzergrenadier Division. At dawn on 14 Dec, Canadian troops attempted to flank “The Gully” by attacking Casa Berardi to the west, capturing the roads leading into the town by 0750 hours and then the town itself in the afternoon.
After sundown on 13 Dec, 17th Infantry Brigade of Indian 8th Division toward Caldari; the fighting lasted through the following day, capturing roads between Ortona and Orsogna. By the evening on 15 Dec, the Indian troops began to make considerable breakthroughs, complemented by New Zealand troops’ favorable progress at Orsogna. On 16 Dec, the Germans launched a counterattack at positions held by New Zealand at 0315 hours, which would be repulsed, exhausting both sides in the process.
In the morning of 18 Dec, Canadian artillery pieces mounted a heavy barrage on German positions in “The Gully”, followed by an assault by Canadian and Indian troops across the Ortona-Orsogna road; this attack saw initial successes, but it was ultimately repulsed with heavy losses. Two days later, in the afternoon, the Canadians mounted yet another attack, only to find that the Germans had already evacuated “The Gully” and had fallen back into Ortona. Although Ortona would be taken by the Allies by 26 Dec, by this time British 8th Army had been exhausted. An attempt was made on the final day of 1943 to send a small party toward Pescara, but the heavy snowstorm that hindered this advance party only confirmed that the British 8th Army needed time to regroup before it could launch another offensive especially as weather conditions were about to change for the worse.
Toward the western coast of Italy, the US 5th Army was suffering from similar problems. Although the Germans were slowly being pushed back from the Bernhardt Line back toward the Gustav Line, and the Americans were indeed able to launch another offensive in the half of Jan 1944, capturing Monte Porchia, Monte Chiaia, Cervaro, and Monte Trocchio, the northward advance along the Tyrrhenian Sea coast was to be halted as well to regroup before challenging the western end of the German Gustav Line.