The 113th Brigade was originally raised in the First World War from men volunteering for Lord Kitchener's New Armies, and was assigned to the 38th (Welsh) Division.
The brigade, composed entirely of four battalions of the Royal Welsh Fusiliers, served in the trenches of the Western Front throughout the war.
The 113th Brigade was constituted as follows during the war:[1] The brigade and division were both disbanded after the war, but were reformed in the Territorial Army (TA), the British Army's part-time reserve force, in the latter half of 1939 as war with Nazi Germany seemed increasingly likely.
As a consequence of this, the Territorial Army was ordered to be doubled in size, with each unit forming a 2nd Line duplicate.
The 113th Brigade, under the command of Brigadier Llewellyn Alston, was formed as a duplicate of the 160th Infantry Brigade and initially consisted of two TA battalions, the 15th and 2/5th, of the Welch Regiment and one, the 4th, of the Monmouthshire Regiment.