The 1st Division was formed during the Peninsular War in Spain and Portugal, part of the army commanded by General Arthur Wellesley, later 1st Duke of Wellington.

[13] After the retreat from Dunkirk it remained in the United Kingdom on home defence against a German invasion until early 1943 when it was sent to North Africa to take part in the Campaign in Tunisia.

[14] The brigade continued to fight in numerous battles around Anzio and even when not, were still subjected to almost constant artillery, mortar or small arms fire.

In October 1944, while the 3rd Brigade was fighting on the Gothic Line with the Eighth Army, Private Richard Henry Burton of the 1st Battalion, Duke of Wellington's Regiment was awarded the Victoria Cross.

During the Suez Crisis the brigade was moved to Malta, in August 1956, from where they went to Egypt on the aircraft carrier HMS Theseus, reaching Port Said just as the ceasefire was declared.

[18] From 1972, the 3rd Infantry Brigade was headquartered in the Kitchen Hill Factory in Lurgan until moving to the Mahon Road Barracks in Portadown in late 1976, under HQ Northern Ireland and was the HQ element for the security forces which controlled the South Armagh region of Ulster, including several battalions of the Ulster Defence Regiment.