In order to meet NATO, EU, national or multi-national requirements.
The ARRC's history began in 1815 when its antecedent - the 1st Corps - had its weight thrown against Napoleon's forces by the Duke of Wellington at the Battle of Waterloo. At the head of the Corps was its first commander, 23-year-old Major General William, Prince of Orange, who was ultimately wounded during the battle. Noteworthy of the 1st Corps during the battle is that it was comprised of British, Anglo-Hanoverian and Dutch-Belgian troops. Historian Dr Edward Flint states that, "The multinational nature of Allied forces at Waterloo is a reminder that such arrangements are not exclusive to the post-Cold War era."
After Waterloo corps formations in the British Army largely disappeared for all intents and purposes, but by 1899 the 1st Army Corps was raised and mobilised to facilitate forces to South Africa in support of the Boer War. It afterward underwent a period of various schemes and by the onset of the First World War in 1914 it found itself comprised of two divisions with each boasting three infantry brigades, three field artillery regiments (eighteen 18-pdr guns each), a field howitzer regiment (eighteen 4.5-inch howitzers) and a heavy artillery battery (four 60-pdr guns). The 1st Corps deployed with said complement in August 1914 as part of the British Expeditionary Force where over the proceeding four years it saw action from Mons to Ypres and back. With the 1st Corps leading the way for the BEF in 1914, the 'war to end all wars' eventually saw a grand total of 23 corps committed to action before Axis capitulation in November 1918.
On the eve of the Second World War, 1st Corps was again mobilised as part of the BEF and directed to move to France in early September 1939. By January 1940 it had gained a third division and finally crossed into Belgium on 10 May upon commencement of the German offensive. Fighting ensued, but, despite a successful counterattack near Arras, the Corps, along with the rest of the BEF, was forced to withdraw and evacuate via Dunkirk where 1st Corps formed the rear-guard. Once back in Britain the Corps focused on homeland defence, but its time at home would soon come to an end once again.
Crossing the English Channel for a second time on 6 June 1944 the 1st Corps was tasked with securing Sword and Juno Beaches during the air- and seaborne assaults of Operation Overlord, also known simply as 'D-Day'. The objective of the Corps was to capture the crossings over the Caen Canal and River Orne, neutralise German coastal defences and prevent their reinforcement of Bures and Troan. After more than a month of heavy fighting the 1st Corps liberated Caen. Following the D-Day campaign, the 1st Corps was task organised to the 1st Canadian Army and then participated in combat operations that took the Allies across Northern Europe to Paris, Brussels and Antwerp, the latter of which the Corps more or less remained until the end of the war.
With Hitler's death and the surrender of German forces in the Spring of 1945, the 1st Corps quickly found itself on occupation duty as did the Americans, French and Soviets. Initially, 1st Corps was one of three corps districts within the British sector located in Northwest Germany, but this was short lived as in late May 1945 the Corps was given complete responsibility and aligned under the command of 2nd British Army. During its occupation of Germany the Corps witnessed the mass movement and care of more than 22 million displaced persons, the birth of post-war German newspapers, encouragement of political parties, trade union reform and industrial regeneration. 1st Corps occupation of post-war Germany lasted but two years and the district was disbanded on 1 June 1947.
Upon NATO's establishment in 1949, members established a series of national corps in West Germany to defend against a Soviet attack from the east. Onto the scene in June 1951 came the old British 1st Corps. Newly reflagged as the 1st (BR) Corps its sector of responsibility covered a 65 km-long front and measured 150 km deep, while being flanked by the 1st (German) Corps and 1st (Belgian) Corps. The scale of the Red Threat it faced was daunting; even when the Soviet Army reduced its size in the late 1950s, the technological, operational and strategic developments made by the Soviet Union and their Warsaw Pact allies kept the Alliance on its toes. In response, 1st (BR) Corps underwent a series of modifications adapted for a nuclear battlefield, which saw multiple iterations with regard to scaling, relationship and ratios of divisions and brigades. Operational art adapted, too, which saw the development of more substantial screening troops (anything up to a division) to the Corps. Force structure and materiel changes were not the only changes; there were geographical changes as well with defence lines changing periodically as the Cold War progressed. Initially, the Rhine was more likely, later the Weser was preferred and later still it was somewhere closer to the Inner German Border. As defences moved eastwards the need for greater conventional strength to offset the inevitable delay in the nuclear decision was needed. All changes aside, the aim of NATO did not change, which was to fight the Red Army for thirty days or more in order to allow a political dialogue to begin. When it was all said and done in 1989, the 1st (BR) Corps met its end of the agreement by maintaining a ready presence for nearly 40 years to counter any advance the Soviets may have had in mind.
With the end of the Cold War came optimism, but also uncertainty about potential trouble and hotspots along NATO's periphery and its ability to react. Thus, from the beginning of the 1990s and then confirmed by events in Yugoslavia, Moldova and Kuwait, the need was established for a force of suitable size capable of deploying and responding to crises andchallenges with speed. To generate the balance between weight and speed a 'rapid reaction corps' was proposed by the British. From the start it adopted a multinational flavour that would allow expertise and relevance to be maximised, whilst maintaining the deterrent and unity effects of Alliance armed forces standing together. Initially called the Allied Command Europe Rapid Reaction Corps and the direct successor of the old 1st Corps, the ARRC was born on 1 October 1992 in Bielefeld, Germany and then moved to Rheindahlen in 1994. The British support for the ARRC came in the form of sixty percent of the headquarters staff, a signals brigade, a headquarters support battalion and logistic capability, which it maintains today. During these formative years many of the ARRC's foundations for later success were laid such as the exercise programme, including the annual Exercise ARRCADE FUSION that is still held today.
Since its creation in 1992 the ARRC has deployed four separate times on real-world operations. The first came under Lieutenant General Walker with the implementation of the Dayton Agreement of 22 November 1995, bringing an end to the civil war in Bosnia; it also happened to be NATO's first out of area operation. The Implementation Force (IFOR) used the ARRC to act as headquarters to three multinational divisions who had responsibility for a 180-kilometer long ceasefire line and ensured compliance amongst the warring factions with the 'zones of separation' and 'cantonment' of forces.
The ARRC's second deployment came in 1999 under Lieutenant General Jackson as a result of deteriorating conditions in Kosovo. Five brigades from France, Germany, Italy, the United States and Britain were initially allocated to the ARRC as part of Kosovo Force (KFOR) with Britain later adding a second brigade. The ARRC in KFOR was unusual in having no intermediary divisional headquarters. When Serbian leadership finally backed down in Kosovo, the ARRC turned its attention toward instituting order and maintaining a safe and secure environment, which continues to be the primary focus today for the current KFOR mission.
The post-911 era has seen the ARRC deploy twice more, both to Afghanistan. The involvement of the ARRC in assuming responsibility for the headquarters of International Security Assistance Force (ISAF) in Afghanistan in 2006 under Lieutenant General Richards brought with it new NATO 'firsts'. It was the first time a single headquarters ran all the sectors of Afghanistan (through Regional Commands). It was also the first time since the Second World War that a sizeable contingent of United States forces (45,000) came under a non-American commander in a time of war. It was also the first time that NATO fought a combined arms battle when it attacked the entrenched Taliban position south of Kandahar. The ARRC redeployed in early 2007, but deployed for the fourth time in 2011 where 200 of its members supplemented the ISAF Joint Command (IJC) for a period ranging from six to 12 months.
In 2017 the ARRC was tasked with responsibility for the land component of the NATO Response Force (NRF) and played an integral part in one of NATO's capstone exercises, Exercise NOBLE JUMP 2017, which saw for the first time Allied troops deploying by land, air and sea to NATO's periphery in Romania. The ARRC relinquished it responsibilities as the land component of the NRF on 10 January 2018 to NATO Rapid Deployable Corps - Italy. When not in role as the NRF, the ARRC may be required to mobilise to assist the standing NRF thus becoming an intermediary headquarters. NATO's long term formation rotation plan allows headquarters like the ARRC to prepare and remain focused. Through a tough and regimented training schedule, it is no surprise, then, that today's ARRC, like the British 1st Corps that came before it, is the tip of the spear in the realm of corps warfighting.