Colonel Mahon, a young Irish officer who had made his reputation as a cavalry leader in Egypt, had started early in May from Kimberley with a small but mobile force consisting of the Imperial Light Horse (brought round from Natal for the purpose), the Kimberley Mounted Corps, the Diamond Fields Horse, some Imperial Yeomanry, a detachment of the Cape Police, and 100 volunteers from the Fusilier brigade, with M battery R.H.A. and pom-poms, twelve hundred men in all. Whilst Hunter was fighting his action at Rooidam on May 4th, Mahon with his men struck round the western flank of the Boers and moved rapidly to the northwards. On May 11th they had left Vryburg, the halfway house, behind them, having done one hundred and twenty miles in five days. They pushed on, encountering no opposition save that of nature, though they knew that they were being closely watched by the enemy. At Koodoosrand it was found that a Boer force was in position in front, but Mahon avoided them by turning somewhat to the westward. His detour took him, however, into a bushy country, and here the enemy headed him off, opening fire at short range upon the ubiquitous Imperial Light Horse, who led the column. A short engagement ensued, in which the casualties amounted to thirty killed and wounded, but which ended in the defeat and dispersal of the Boers, whose force was certainly very much weaker than the British. On May 15th the relieving column arrived without further opposition at Masibi Stadt, twenty miles to the west of Mafeking.