The 1st Division was an infantry division of the British Army that was raised on 18 June 1809 for service in the Peninsular War. The division served under Arthur Wellesley in Spain and Portugal before fighting at the Battle of Quatre Bras and the Battle of Waterloo in 1815. With the end of the Napoleonic Wars, the division took part in the occupation of France until December 1818, when it disbanded upon the British withdrawal. The division was later revived during the Crimean War, Anglo-Zulu War, and the Second Boer War, and a permanent 1st Division was founded in 1902. The division served on the Western Front of World War I, during which General Samuel Lomax was mortally wounded and 16,000 of its soldiers were killed. The division participated in the occupation of the Rhineland after the war, and some of its units participated in the occupation of Constantinople and in the Irish War of Independence. In 1935, the division was redeployed to Mandatory Palestine during the Great Arab Revolt.
On the eve of World War II, most of the regiment's soldiers came from Buckinghamshire, Berkshire, Hampshire, Wiltshire, Gloucestershire, and other counties in southern and central England. In 1939, the division was sent to France and Belgium on the start of World War II, taking part in the fighting that led to the evacuation of Dunkirk in June 1940. The division was later redeployed to North Africa in March 1943, participating in the capture of Tunisia. The 1st Division went on to take part in the invasion of Italy at the Battle of Anzio in 1944, during which it suffered heavy losses; 8,868 officers and men were killed, wounded, or missing during that campaign. The division returned to Palestine after the war, and it later spent time in Egypt and Libya before being attached to the British Army of the Rhine. The division was reorganized as an armored division in 1978, participating in the Gulf War, and the division was again disbanded in 1992. The division later reformed to fight in the Iraq War, and, in 2014, the 1st (United Kingdom) Division was created.