Soon after the outbreak of the Great War, following many years of part-time soldiering as cavalry troops on home defense duties, the members of various British Yeomanry regiments were asked to volunteer for overseas service. In 1916, officered by well-known members of the landed gentry, two of the Welsh Yeomanry regiments, the Pembroke Yeomanry and the Glamorgan Yeomanry, were amongst many who embarked for foreign service for the first time ever in their history. Spending the next twelve months in Egypt during the campaign against the Senussi tribesmen, the two regiments merged to form the 24th (Pembroke and Glamorgan Yeomanry) Battalion, Welsh Regiment, which joined the 74th (Yeomanry) Division to take part in the historic offensive into Palestine that ultimately led to the liberation of the Holy City of Jerusalem after 400 years of Ottoman rule. In May 1918, after two years of hard campaigning in the Palestinian deserts, the 24th Welsh embarked for France with the rest of the 74th Division, joining the Allied forces in the victorious 100-day offensive against the Germans.

Welsh Yeomanry at War sheds new light on the battalion's almost forgotten campaign in Palestine, which saw many of its troops killed and buried in the Holy Land, and also tells the enthralling story of its short but arduous period in France.