The Allied strategy

While plans were being made for the Normandy landings, the Allied strategy in Europe included an attack on Italy, which Winston Churchill called "the soft underbelly of Europe."
Following the North African campaign, the Allies landed in Sicily on July 10, 1943, in an operation codenamed "Husky." As they advanced toward northern Italy, the British and Americans increasingly disagreed about the strategies to be adopted in the European theater, particularly in Italy. The armies were advancing toward the Apennines and the German defenses of the Gothic Line, which German General Albert Kesselring renamed the Green Line in June 1944.

Churchill hoped to bypass or break through the Green Line and race across the Po Valley to reach Vienna and the Balkans via Trieste and the Ljubljana Pass. Churchill hoped to bypass or break through the German defenses of the Gothic Line and race across the Po Valley to reach Vienna and the Balkans via Trieste and the Ljubljana Pass in order to prevent the Russians from expanding their “influence” in the Balkans.

Disagreements arose when, against Churchill's wishes and at the strong insistence of Roosevelt, Operation Anvil-Dragon was decided upon. This operation involved the landing of Allied forces in southern France on August 15, 1944.

This landing served only to divert divisions from the Italian front, weakening the Allied attack and allowing the Germans to stop it. This left the Russian armies free to penetrate the Balkans.

The Americans felt pressured by Stalin to open new fronts even though they knew the fighting in Italy was distracting German divisions from other fronts. However, the Americans weren't interested in the Italian front, believing that all forces should focus on invading France.

Normandy offered the shortest route for the Allied armies to occupy Germany's industrial areas, so the southern France landing was seen as a diversion to draw German divisions away from the northern French front. Ultimately, the landing in southern France served almost no purpose. If the divisions engaged there had remained in Italy and been used for a landing behind German lines—for example, along the Adriatic coast toward Cervia—the outcome of the Battle of the Gothic Line certainly would have been different. The war in Italy certainly would have been shorter, and the basis for the subsequent Cold War certainly would have been different.

The strategy, the Allied and German deployments at dawn on the day of the attack on the Gothic Line: The Operation Olive.

At the Tehran Conference, which took place from November 28 to December 1, 1943, Churchill, Roosevelt, and Stalin discussed two potential operations that could be launched from Italy in conjunction with the Allied landing in Normandy: a landing of troops in southern France or the Balkans.

Stalin opposed the idea of landing in the Balkans, which he considered his sphere of influence. He preferred a landing in southern France. Churchill believed it would be better for the Allies to use these resources in the Italian theater of operations.

Alternatively, he favored a landing to seize the oil fields in the Balkans from the Germans and prevent the advance of the Red Army. This would give the Allies a stronger position at the negotiating table for the postwar settlement in Europe. Despite General Marshall's insistence, Roosevelt deemed the operation unfeasible and canceled it.

After the Normandy landings, the plan was implemented. Bearing in mind Stalin's objections at the Tehran Conference and General Eisenhower's opposition to diverting substantial forces to the Balkans, Roosevelt practically forced Churchill to land in southern France. Known for his stubbornness, Churchill never abandoned the idea of opposing the Red Army's advance in the Balkans and Austria, which would result in Soviet influence in those territories. Even during the fighting on the Gothic Line, he constantly urged the commanders of the 8th British Army, deployed in the eastern Apennines, to break through the German lines, quickly cross the Po River, head north, and reach Trieste and the Ljubljana Pass as soon as possible.

General John Harding, Chief of Staff to General Harold Alexander, commander of the Allied armies in Italy, first drafted the plan to attack the Gothic Line. On June 28, 1944, the 8th Army staff suggested three attack directives: A in the Adriatic sector, B on the Florence-Bologna line, and C in an intermediate sector. After listing the advantages and disadvantages of each plan, they identified plan B as the best. However, General Oliver Leese was concerned about the loss of seven divisions assigned to Operation Dragon, as well as the departure of the French Expeditionary Corps, which would further weaken the 5th Army. He believed that it would be impossible to break through the German defenses north of Florence with armored vehicles. Additionally, he did not want to fight alongside General Mark Clark, commander of the US 5th Army, after Clark had excluded the British from entering Rome. Therefore, Leese suggested a new plan: Operation Olive, which involved a main attack on the Adriatic coast by the 8th Army, supported by a delayed attack by the US 5th Army on the Florence-Bologna line, with 24 hours' notice.

In early March 1945, the 8th Army was slowly advancing through the Romagna region along the Via Emilia. Shortly before the spring offensive on April 14, General Mark Clark—who had taken over for General Harold Alexander on December 12, 1944—adopted a new strategy. He had noticed that most of the German defenses were concentrated south and east of the Reno River. The river heads north towards Bologna and bends towards the Adriatic coast, forming a pocket after penetrating deep into the Po Valley. With Operation Olive, Clark planned to attack with the II Corps east of the river, from the Giogo and Futa passes toward Imola. However, the main thrust would be west of the Reno River, toward Bologna, by the IV Army Corps. This corps consisted of the 10th Mountain Division, assisted by the 1st Brazilian Infantry Division. They were in an optimal starting position.

After exiting the mountains and attempting to destroy the encountered German divisions, the road to the Po River would present no significant obstacles. Upon reaching the Via Emilia in the Po Valley, the 5th Army divisions, now under the command of General Lucian Truscott, would closely pursue the retreating German soldiers from the Apennines. This would prevent the Germans from reorganizing their defenses on the Po River banks and cut off the retreat of the remaining German divisions coming from the east. The British 8th Army would pursue them, trapping them and preventing them from establishing themselves on the Adige River defense line. Finally, they would be trapped in the mountains of the northeastern Alps, near the Austrian border, where they could have entrenched themselves to defend Germany's southern border after destroying the industrial resources in the Po Valley.

From the German perspective, Adolf Hitler ordered General Kesselring, and then his successor, General Heinrich von Vietinghoff, to slow the Allied advance on the Italian peninsula as much as possible while awaiting the operational readiness of new weapons: the V1 and V2 missiles, as well as the ME 262, the world's first jet-powered aircraft, developed by Third Reich scientists in Germany. Hitler was convinced that these new weapons would turn the tide of the war. Additionally, the industrial and agricultural apparatus of northern Italy had to continue supplying Germany and its war effort. Kesselring carried out his task with Teutonic efficiency, adopting the tactic of elastic defense. This cost the Allies time, men, civilians, and material destruction.

The largest defense network that the Allies had to contend with in Italy was called the Gothic Line (Gotenstellung) by the Germans. As the Allied armies approached in June 1944, Kesselring renamed it the Green Line (Grüne Linie).

The defenses, prepared by the Todt Organization, stretched 320 km across the northern Apennines. They began in the Magra River valley, a few kilometers south of La Spezia, and crossed the strategic massifs of the Vernio Pass north of Prato and the Futa Pass north of Florence. They continued along the Foglia River valley and ended on the Adriatic Sea slopes between Pesaro and Cattolica.

The powerful defenses also extended inland for about twenty kilometers. In fact, the two main lines of resistance were called the Gothic Line I and II (Linea Verde). Up to the Arno front, the U.S. Fifth Army and the British Eighth Army advanced along the Tyrrhenian corridor. In mid-August, in accordance with Operation Olive plans, the British 8th Army was secretly transferred from the Tyrrhenian front to the Adriatic front.

At the start of the attack on the Gothic Line:

The British 8th Army had about 410,000 soldiers, including 61,000 Polish soldiers from the 2nd Polish Corps, 53,500 Canadian soldiers from the 1st Canadian Corps, 117,000 British and Indian soldiers from the British 5th Army Corps, 40,000 New Zealand soldiers, 38,500 Anglo-Indian soldiers from the X Corps, and 100,000 other soldiers, such as those from the 209th and 228th Italian Auxiliary Divisions.

The US 5th Army on the Tuscan-Emilian Apennine Front had the following forces: the II Corps (34th, 88th, and 91st US Infantry Divisions); the IV US Army Corps with about 171,000 men (1st US Armored Division, 6th South African Armored Division, and 1st Brazilian Infantry Division (F.E.B.), the 92nd American Infantry Division, and the 45th American Task Force, the 210th Italian Auxiliary Division and several partisan brigades and four divisions of the XIII British Corps. In total, the 5th US Army had about 300,000 men. In January 1945, the 10th U.S. Mountain Division arrived on the front line. The 92nd Division and the Brazilian Expeditionary Force were considered weak points due to their inexperience and perceived inability to attack effectively, as their commander, General Mascarenhas de Morais, admitted to General Mark Clark.

By the end of August 1944, General Albert Kesselring, commander of Army Group C, had 13 divisions in position, including the 10th Army, commanded by General Heinrich von Vietinghoff, and the 14th Army, commanded by General Joachim Lemelsen. Each army had 12,700 soldiers, for a total of approximately 98,800 combatants and 66,300 support personnel. The reserve consisted of seven divisions. In total, 339,000 men defended the Gothic Line, including 180,000 combatants and 159,000 service personnel.

Ultimately, the Allies had numerical and equipment superiority, including superiority in artillery, ships, tanks, and aircraft. The omnipresent Allied air force provided considerable support for the operations.

In the summer of 1944, partisan forces numbered between 50,000 and 70,000 men, according to censuses by Ferruccio Parri and Giorgio Bocca, respectively. In Emilia-Romagna, there were: The 8th Garibaldi Brigade "Romagna," commanded by "Pietro" (Ilario Tabarri); the 28th Garibaldi Brigade "Gordini" of Ravenna, commanded by "Bardi," though under the effective command of "Bullow" (Arrigo Boldrini); The 36th "Bianconcini" Brigade was commanded by "Bob" (Luigi Tinti) on the Santerno; the Red Star was commanded by "Lupo" (Mario Musolesi) between the Setta and Reno rivers; and the "Modena" was commanded by "Armando" (Mario Ricci).
The Allies did not trust these guerrilla formations very much.
There were fears of a "second Greece"; in mid-October 1944, the British became involved in a civil war between the ELAS partisans and the government led by Georgios Papandreou. The Italian partisans were certainly considered important, and the Allies knew they would contribute to the final offensive. However, as the war was drawing to a close, the Allies wanted to keep this help under close control. As soon as the partisans had completed their tasks, they were disarmed. The thought of thousands of heavily armed partisans moving through the cities of northern Italy, declaring that revolution was imminent, was a prospect that the Allies and the military occupation administration did not dare consider. Whatever the chances, it was a risk they were not willing to take. Quelling a possible armed uprising after the long, bloody campaign against Germany and the RSI was not a pleasant thought.

Starting in the summer of 1944, partisan actions began to cause problems for the Germans. They suffered 5,000 deaths and between 7,000 and 25,000 wounded in two months, depending on the source. The anti-partisan struggle was mainly carried out by soldiers of the Italian Social Republic. According to the German OKW, their numbers totaled about 498,000 men in September 1944. This included the army (143,000), navy (26,000), air force (79,000), Italian SS (10,000), 29th Italian SS Grenadiers (90,000), volunteers in German units (90,000), and the G.N.R. (150,000), including the "Etna" Division. Prominent formations that fought alongside the Germans included the Lupo Battalion of the X Mas, the "M" Guardia del Duce, and the Tagliamento Legion on the Adriatic front, as well as the 8th Bersaglieri Manara. On the Tyrrhenian front, the Armata Liguria, commanded by Marshal Rodolfo Graziani, comprised the 3rd Marine Division S.Marco, the 4th Alpine Division Monterosa, and the 1st Bersaglieri Italia Division, all of which were trained in Germany.