At the time of the Boer trek, the great power in central and eastern South Africa was the Zulu nation. Under their renowned chief Tchaka, one of the most remarkable military geniuses of history, possessing to the full the vices and virtues of his type, the small Zulu tribe had become a great nation, dominating over and treading down other native tribes and races. Killing the older men and women and absorbing the youths and maidens into his own people, as he conquered tribe after tribe, he had by his wonderful military discipline produced a vast army of warriors, before whom no native people could stand. In 1828, Tchaka was assassinated by his half-brother Dingaan, who, without sharing his genius, possessed his fault as a ruthless destroyer of men. At the time of the Great Trek, Dingaan ruled over the Zulu nation and its dependencies in Natal and Zululand. In the Transvaal, a division of the Zulus, which had broken from Tchaka under their celebrated warrior-chief Umsiligaas, had, under the name of the Matabele, founded a great warrior nation, moulded after the ideal of Tchaka; they devastated the lands and destroyed the native tribes which resisted their power. When the first party of the fore-trekkers under Potgieter arrived in the northern districts of the Free State, the native tribes there welcomed them as a possible assistance against the inroads of the powerful Matabele. The whole country was in those days filled with game to an almost inconceivable extent, and it was largely on the fruit of the gun that the fore-trekkers lived. In 1836 their first great conflict with the Matabele under Umsiligaas took place. The fore-trekkers had spread themselves out in small parties, camping with their wagons near the Vaal River, and the Matabele attacked them wherever they were found in small numbers. Near what is now known as Erasmus Drift on the Vaal River, a small party in five waggons was suddenly surrounded and several of the Boers were killed. Barend Liebenberg's little party was taken by surprise, and six men, two women, and four children, with twelve native servants were destroyed, and three white children, a boy and two girls, carried away captive. The great Matabele army then rapidly advanced to where the main body of the emigrants had encamped at a spot now known as Vechtkop, about twenty miles from the present village of Heilbron, in the Free State. Paul Krüger, then a child, can still remember the preparations for defence, and relates how the wagons were drawn up in a square, mimosa branches cut down and dragged to the wagons, women and young children helping in the labour; and how these branches were tied together by chains to fill in the spaces between the fore and back wheels of the wagons to prevent the Matabele warriors from crawling up between them.