The 6th Royal Lancashire Militia was an auxiliary regiment raised in the county of Lancashire in North West England just before the Crimean War. It later became part of the Manchester Regiment. Although primarily intended for home defence, its battalions saw active service during the Second Boer War. Following conversion to the Special Reserve (SR) under the Haldane Reforms it supplied reinforcements to the fighting battalions during World War I. After a shadowy postwar existence the unit was finally disbanded in 1953.

The 91st Brigade was an infantry formation of the British Army during World War I. It was raised as part of 'Kitchener's Army' and was assigned to the 30th Division. After the original formation was converted into a reserve brigade, the number was transferred to a brigade of 'Manchester Pals'. The brigade landed in France at the end of 1915 and was transferred to the Regular 7th Division. It saw action at the Somme, Arras, and Ypres before being sent to the Italian Front, where it took part in the final Battle of Vittorio Veneto. The brigade's number was briefly revived during the 1950s.