In January 1878 Warren proceeded to the Gaika war in command of the Diamond Fields Horse, raised at Kimberley, and was engaged for six months in Kaffraria. He bought his mounts and drilled his men on the way, and infused his own indomitable energy into every member of his command. He took part in numerous engagements, among which may be mentioned the action of Perie Bush in March, when he was injured by the falling of the bough of a tree, and the action at Debe Nek on 5th April, where with seventy-five of the Diamond Fields Horse he met 1,200 armed Kafirs of Seyolo’s tribe in the open, and gained a complete victory. The Governor-in-Chief telegraphed his congratulations on this brilliant success. A few weeks later Warren had another successful fight at Tabi Ndoda on 29th April, when he was slightly wounded. He was frequently mentioned in despatches, and his conspicuous personal bravery, no less than his skill as a commander, was brought to the notice of the Secretary of State for War. The Governor-in-Chief especially commended him in his despatches for ‘energy, ability, and resource displayed under most trying circumstances.’ He had been promoted to be Major on 10th April 1878, and his services in the campaign were recognised by a brevet-lieutenant-colonelcy, dated 11th November 1878, and the South African medal. _Native Rebellion in Griqualand West and Troubles with the Bechuanas, 1878-9_ Early in May the whole native population of Griqualand West, west of the Vaal river, broke out in rebellion and, joining their former enemies, the Kaal Kafirs (refugees from Cape Colony), commenced depredations to the west of Griquatown. In consequence of this critical state of affairs in Griqualand West the Executive Government telegraphed for the assistance of Warren and the Diamond Fields Horse from the Cape Colony. The regiment left King William’s Town on 14th May and arrived at Griquatown on 10th June.