Within the Commonwealth War Graves Commission book of names for Ferme Olivier cemetery, Belgium there is an entry that briefly relates to a particular group of soldiers who are buried there -

...a collective grave in Plot 2, Row E, contains the remains of 37 men of the 3rd Battalion Monmouthshire Regiment killed on parade on 29th December 1915 by a single shell fired from a naval gun in Houthulst Forest. [Source - CWGC]

During a war that was filled with tragedy, the background to these deaths must be among the saddest.

Throughout the later months of 1915, companies of the 3rd Battalion, Monmouthshires had been heavily engaged in a wide variety of actions near the Yser Canal area just north of Ypres in Belgium. This was not limited to fighting action, but also building and maintaining drainage channels from the waterlogged Flanders mud which formed the trenches. They also built footbridges in order to traverse the thick mud which would often make men disappear by sinking into the mud. They carried out these duties while under fire from German positions who were not far away.

During November and December 1915, German shelling was particularly bad and in December there were further warnings of gas attacks forthcoming. At about 5.30 am on 19th December A and C companies had a lucky escape when they moved back to forward trenches, for, at about 7 am that day German shelling was landing where they had been just a few hours before.

On 29th December 1915 the Battalion reassembled in their camp at Elverdinghe, behind the front lines. They were preparing for a withdrawal from the area for a well earned six weeks of rest and had received orders to parade ready to move off at 2.30 pm.

While on parade a single shot was fired by the Germans which burst above Elverdinghe Chateau nearby. This was just a ranging shot for the German artillery. A few minutes later, the first of four German artillery shells exploded between B and C Company while they paraded, killing thirty nine and injuring thirty. William Probert was among those killed outright.

When the Battalion did leave the Ypres salient on this occasion, it was the last time that they would be there as The Third Battalion, Monmouthshire Regiment. In 1916 the remaining men were absorbed in to the ranks of other battalions who had suffered heavy losses.