Mfecane (isiZulu), also known as the Difaqane or Lifaqane (Sesotho), is an African expression used about chaos and disturbances. It probably means something like "the Crushing", and originates from the events leading to the rise to power of chief Shaka. This Zulu chief conquered the Nguni peoples between the Tugela and Pongola rivers in the beginning of the 19th century, and created a militaristic kingdom.
There are varying theories on the origins of this catastrophic, bloody migration of many different tribes in the area. Populations had increased greatly in Zululand. The introduction of corn from the Americas through the Portuguese in Mozambique was a factor. Corn produced more food than indigenous grasses on the same land, and thus could sustain the larger population, at the price of greater water usage. It also allowed Shaka to raise a standing army, growing crops not being a part of their duties.
By the end of the 1700s much of the arable land was now occupied. Declining rainfall, and ten-year drought in the early 1800s meant that a battle for land and water resources began in earnest. Battles between Dingiswayo of the Mthethwa clan in the south near the Tugela River and Zwide of the Ndwandwe from the north near the Pongola River probably marked the start of what became the Mfecane. After the Mthethwa were beaten by Zwide, and Dingiswayo killed, the power vacuum was filled by the Zulus, under the ambitious leadership of Shaka. Shaka conquered smaller clans in the area, and the Battle of Gqokli Hill marked the start of his conquest of the Ndwandwe.
Shaka assimilated conquered tribes, but usually just the women and young men. The rest were either killed or escaped. Escapees quickly learned the tactics of the Zulus, and in turn descended upon more distant clans unfamiliar with the new order.
To the east, escapees were assimilated into the Xhosa in present day Eastern Cape Province, becoming the Mfengu. They were subjected to successive waves of attack, and were pressed from the West by the British.
Moshoeshoe I of Lesotho gathered the mountain clans together, and from mountain forts and with fine diplomacy fought back against the aggressors, to eventually form the kingdom of Lesotho.
Soshangane, one of Zwide's generals, fled to Mozambique with the remainder of the Ndwandwe after their defeat by Shaka at the battle of Mhlatuze River. They oppressed the Tsonga living there, some of whom fled over the Lebombo Mountains into the Northern Transvaal.
The Ngwane people lived in present-day Swaziland, settled in the southwest, and warred periodically with the Ndwandwe. Ngwane leader Sobhuza led his people to higher elevations around 1820 to escape Zulu attacks. In this period the Ngwane became known as the Swazi, and Sobhuza established the Swazi kingdom in what is now central Swaziland.
A Zulu general Mzilikazi broke away from Shaka and established the Ndebele kingdom in the Orange Free State/Transvaal area. When white trekboers in the Great Trek moved into the area in 1837, defeats in several clashes convinced Mzilikazi to move north of the Limpopo River and establish his kingdom there, known historically as the Matabele Kingdom in Rhodesia/Zimbabwe.