Army Group A in the context of "Fall Rot"

During World War II, the Crimean Peninsula was subject to military administration by Nazi Germany following the success of the Crimean campaign. Officially part of Generalbezirk Krym-Taurien, an administrative division of Reichskommissariat Ukraine, Crimea proper never actually became part of the Generalbezirk, and was instead subordinate to a military administration. This administration was first headed by Erich von Manstein in his capacity as commander of the 11th Army and then by Paul Ludwig Ewald von Kleist as commander of Army Group A.

German interests in Crimea were multifaceted and a matter of great sensitivity due to German–Turkish relations, with Turkey serving as the primary champion of the rights of Crimean Tatars. Basing their interests in Crimea off of the historical existence of the Crimean Goths (the last surviving Gothic peoples), German authorities sought to transform Crimea into a tourist destination, including the deportation and genocide of Crimea's non-German inhabitants. Plagued by Soviet resistance from the outset of occupation, they failed to establish order to any extent that allowed for colonisation to take place, and lost further support due to the slow pace of land reform programmes and a lack of response to Crimean Tatar nationalist sentiment.

The Crimean campaign was conducted by the Axis as part of Operation Barbarossa during World War II. The invading force was led by Germany with support from Romania and Italy, while the Soviet Union took up defensive positions throughout the Crimean Peninsula. The Axis offensive routed the Red Army and enabled the three-year-long German occupation of Crimea.

Beginning on 26 September 1941, the German 11th Army and the Romanian Third Army and Fourth Army were involved in the fighting. They were opposed by the Soviet 51st Army and elements of the Black Sea Fleet. After the campaign, Crimea was occupied by Germany's Army Group A, with the 17th Army as a major subordinate formation.

The Manstein plan or Case Yellow (German: Fall Gelb; also known after the war as Unternehmen Sichelschnitt a transliteration of the English Operation Sickle Cut), was the war plan of the German armed forces (Wehrmacht) for the Battle of France in 1940. The original invasion plan was an awkward compromise devised by General Franz Halder, the chief of staff of Oberkommando des Heeres (OKH, Army High Command) that satisfied no one. Documents with details of the plan fell into Belgian hands during the Mechelen incident on 10 January 1940 and the plan was revised several times, each giving more emphasis to an attack by Army Group A through the Ardennes, which progressively reduced the offensive by Army Group B through the Low Countries to a diversion.

In the final version of the plan, the main effort of the German invasion was made against the Ardennes, the weakest part of the Allied line, where the defence was left to second-rate French divisions in the Second Army and the Ninth Army, on the assumption that the difficulty of moving masses of men and equipment would give the French plenty of time to send reinforcements if the area was attacked. The Seventh Army, which had been the most powerful part of the French strategic reserve, had been committed to a rush through Belgium to join with the Dutch Army to the north, in the Breda variant of Plan D, the Allied deployment plan.

Karl Rudolf Gerd von Rundstedt (12 December 1875 – 24 February 1953) was a German Generalfeldmarschall (Field Marshal) in the Heer (Army) of Nazi Germany and Oberbefehlshaber West (Commander-in-Chief in the West) during World War II. At the end of the war, aged 69, with over 52 years of service, he was the Army's most senior officer.

Born into a Prussian family with a long military tradition, Rundstedt entered the Prussian Army in 1892. During World War I, he served mainly as a staff officer. In the interwar period, he continued his military career, reaching the rank of Generaloberst (Colonel General) before retiring in 1938. He was recalled at the beginning of World War II as commander of Army Group South in the invasion of Poland. He commanded Army Group A during the Battle of France, and requested the Halt Order during the Battle of Dunkirk. He was promoted to the rank of Field Marshal in 1940. In the invasion of the Soviet Union, he commanded Army Group South, responsible for the largest encirclement in history, the Battle of Kiev. He was relieved of command in December 1941 after authorizing the withdrawal from Rostov but was recalled in 1942 and appointed Commander-in-Chief in the West.

The Battle of Sedan or Second Battle of Sedan (12–15 May 1940) took place in World War II during the Battle of France in 1940. It was part of the German Wehrmacht's operational plan codenamed Fall Gelb (Case Yellow) for an offensive through the hilly and forested Ardennes, to encircle the Allied armies in Belgium and north-eastern France. German Army Group A crossed the Meuse with the intention of capturing Sedan and pushing westwards towards the Channel coast, to trap the Allied forces that were advancing east into Belgium, as part of the Allied Dyle Plan.

Sedan is situated on the east bank of the Meuse. Its capture would give the Germans a base from which to take the Meuse bridges and cross the river. The German divisions could then advance across the open and undefended French countryside to the English Channel. On 12 May, Sedan was captured without resistance and the Germans defeated the French defences around Sedan on the west bank of the Meuse. German Luftwaffe bombing and low morale prevented the French defenders from destroying the bridgeheads. On 14 May, the British Royal Air Force (RAF) and the French Armée de l'Air jointly tried to destroy the bridgeheads, but the Luftwaffe prevented them from doing so. In large air battles, the Allies suffered high losses which depleted Allied bomber strength in the campaign.

The Battle of Dunkirk (french: Bataille de Dunkerque) was fought around the French port of Dunkirk (Dunkerque) during the Second World War, between the Allies and Nazi Germany. As the Allies were losing the Battle of France on the Western Front, the Battle of Dunkirk was the defence and evacuation of British and other Allied forces to Britain from 26 May to 4 June 1940.

After the Phoney War, the Battle of France began in earnest on 10 May 1940. To the east, the German Army Group B invaded the Netherlands and advanced westward. In response, the Supreme Allied Commander, French General Maurice Gamelin, initiated "Plan D" and British and French troops entered Belgium to engage the Germans in the Netherlands. French planning for war relied on the Maginot Line fortifications along the German–French border protecting the region of Lorraine but the line did not cover the Belgian border. German forces had already crossed most of the Netherlands before the French forces had arrived. Gamelin instead committed the forces under his command – three mechanized forces, the French First and Seventh Armies and the British Expeditionary Force (BEF) – to the River Dyle. On 14 May, German Army Group A burst through the Ardennes and advanced rapidly westward toward Sedan, turning northward to the English Channel, using Generalfeldmarschall Erich von Manstein's plan Sichelschnitt (under the German strategy Fall Gelb), effectively flanking the Allied forces.