 Hunter led them in the march on Pretoria, crossing into the Transvaal Republic on 3 May.Once Pretoria was captured though Robert's army had to deal with Guerrilla warfare and General Hunter was sent south again as overall commander of five columns that converged on the Free State army camped at Brandwater Basin, forcing the surrender of 4,314 Boers led by Marthinus Prinsloo.It was the largest number of Boers captured in the war so far and cost very little in British casualties; only 33 dead and 242 wounded.