Botha had never abandoned the scheme of an invasion of Natal which was drawn up at the end of 1900. His first attempt to carry it out was frustrated by French, but it was uppermost in his mind during the winter of 1901. Early in September he left the Ermelo district, in which Lord Kitchener had never been able to operate effectively, and made for Piet Retief with 1,000 men. Columns, faint yet pursuing, started from each railway, and ignorant of his movements trudged wearily across the veld to the S.E. Botha, after passing through the defile between the Swaziland border and the Slangapiesberg, turned to the south, his ultimate objective being Dundee. In the corner abutting on Zululand were commandos under Emmett and Grobler of Vryheid. Lyttelton on his return from leave took over the Natal command from Hildyard. He disposed his columns as best he could, having regard to the contradictory reports which reached him of Botha's movements and intentions. The first encounter occurred on September 17 at Blood River Poort. A mounted column under Gough and Stewart had been sent out from Dundee across the Buffalo to bring away a convoy from Vryheid. Gough soon came into touch with a body of the enemy. It was, he thought, only a local commando, and when he saw it off-saddle he left Stewart in support and went out to surprise it. The nature of the ground prevented a complete surprise, but he partially effected it, only to be surprised himself by the sudden charge of Botha's main body, which was supposed to be a day's march distant. After a brief combat, in which Stewart was unable to intervene, Gough lost the whole of his command of nearly 300 men in killed, wounded, and prisoners, as well as three guns. Stewart escaped to the Buffalo. The crick-crack of Botha's Mausers at Blood River Poort echoed throughout South Africa. Troops from all quarters were hurried to the spot; search parties discovered some columns under W. Kitchener which had lost themselves on the high veld; and so rarified was the military atmosphere, that not only columns but even general officers were scarce. Bruce Hamilton and Clements were brought in.