During a campaign, a commander in the field wrote back to his higher authority informing them what was happening - who had attacked who, how many casualties had been received, what was the effect of his latest manoeuvre etc. He also mentioned officers and soldiers who had carried out a gallant action or who rendered distinguished service. To be so mentioned was to have been "Mentioned in Despatches".
The despatches were usually printed in the London Gazette, but up to the Great War, being mentioned in a despatch did not result in the officer or soldier receiving any visible mark (for example a medal) to show that he had been mentioned. It was only after the Great War had finished that it was decided to issue a small bronze oakleaf to any officer or soldier who had been mentioned in a despatch. This emblem was usually worn on one of the medal ribbons that he had been awarded.
An example may prove useful. The following appears in the War Services section of Hart's Annual Army List for 1906:
Lieutenant Percy Charles Wildman
Goodwyn, The East Lancashire Regiment.
Lieut Goodwyn served in the South African War in 1900-1902 with the 8th Mounted Infantry; took part in the advance under Lord Roberts from Orange River, including the capture of Cronje's Lager at Paardeberg; present in the advance through Orange Free State, including engagements at Brandfort, Vet and Zand Rivers, occupation of Johannesburg and Pretoria; present in subsequent mounted operations in Western Transvaal, including capture of Delarey's convoy and gun at Vaalbank; also mounted operations in Orange River Colony, and in Eastern Transvaal under General Bruce Hamilton; further operations in Orange River Colony, including the capture of 800 Boers under Commandant Meyers, and in Western Transvaal under General Ian Hamilton (twice mentioned in despatches, DSO, Medal with three clasps)
If we then look at Lord Kitchener's despatch of 8 May 1901, the following can be found:
Lieut P C W Goodwyn, in command of left flank guard with only 10 men, galloped for a spur to which Boers were making. With great gallantry got to close quarters with the enemy, killing one and wounding two. I regret to say that he lost two killed and three wounded, and the remainder were taken prisoners. This attack, made on his own initiative, was of very great assistance in detaining the enemy. Enemy themselves stated that they had 180 men on the kopje.