William Cecil, 5th Marquess of Exeter

William Thomas Brownlow Cecil, 5th Marquess of Exeter (27 October 1876 – 6 August 1956), known as Lord Burghley from 1895 to 1898, was a British peer.

Exeter was the son of Brownlow Cecil, 4th Marquess of Exeter, and his wife, the former Isabella Whichcote. He was educated at Eton and Magdalene College, Cambridge. He succeeded as 5th Marquess on the death of his father on 9 April 1898.

Military career Lord Burghley joined the part-time 3rd (Northampton and Rutland Militia) Battalion, Northamptonshire Regiment (commanded by his father) as a Lieutenant on 24 July 1895. He was promoted to Captain on 22 March 1899. During the Second Boer War the battalion was embodied for home service on 4 January 1900 and he went with it to Barossa Barracks at Aldershot as a supernumerary captain. While there he acted temporarily as aide-de-camp to Major-General John Edward Boyes, with the 7th Brigade. In March the battalion moved to Verne Citadel, Portland,

In May 1910 he was appointed officer commanding of the Northamptonshire Battery, Royal Field Artillery, with the rank of Major. This unit had been formed from the Peterborough companies of the 1st Volunteer Battalion, Northamptonshire Regimen, following the creation of the Territorial Force (TF) in 1908. It formed part of IV East Anglian Brigade, RFA, and Exeter was promoted to Lieutenant-Colonel commanding this brigade on 21 January 1914.

On the outbreak of World War I in August 1914 the brigade was undergoing annual training at Redesdale in Northumberland with the rest of the TF's East Anglian Division (later 54th (East Anglian) Division). They immediately mobilised and served in coast defence until May 1915. When the rest of 54th (EA Division) embarked for the Gallipoli Campaign the artillery remained behind and continued training before going overseas in November. After a brief stay in France, the divisional artillery rejoined 54th (EA) Division in Egypt and went into the Suez Canal defences until January 1917, when they prepared to advance into Sinai.

At this point Lord Exeter was transferred to command XIX Brigade, Royal Horse Artillery, in the Imperial Mounted Division that was being formed. Since a mounted division only had one artillery brigade, he also held the post of Commander, Royal Artillery (CRA) for the division. The Imperial Mounted Division (Australian Mounted Division from June 1917) served through the Palestine Campaign, at the First, Second and Third Battles of Gaza, the defence of Jerusalem after its capture, the Second Trans-Jordan Raid, and the final offensive, including the capture of Damascus. The Marquess of Exeter was twice mentioned in despatches for his services during the war, was promoted to Colonel and awarded a Companionship of the Order of St Michael and St George (CMG).

After the war he remained in the Territorial Army (TA) until he retired in 1933, and served as president of the Northamptonshire TA Association until 1951. He was awarded the Territorial Decoration (TD) and was ADC to King George V 1920–31. orders = The Most Noble Order of the Garter - Knight Companion (KG).