A prophecy by a teenage Xhosa girl, Nongqawuse, which said that the slaughter of cattle and destruction of crops would bring back ancient Xhosa chiefs, who would push the whites back to the sea, that the sun would turn red and a new age begin for the Xhosa. The prophesy was believed by the Xhosa paramount chief Sarili, who instructed his subordinates to carry out the cattle-killing. The expected date for the prophesy was 16 February 1857. The resultant destruction lasted for 15 months (1856-57) and proved catastrophic to the Xhosa people. Over 20,000 people starved to death, many more had to seek refuge across the river in the Cape Colony. Sir George Grey, the Cape Governor used the situation to his advantage, dispossessing Sarili and his people, and giving the land to white settlers and the Mfengu people.
The Cattle-Killing was seen by later generations of Xhosa as a manipulation by Grey, whereas the British attributed it to a plan by Sarili to force the Xhosa into the Cape. It is now viewed as a millenarian response initiated by Nongqawuse's uncle, Mhlakaza (a famed spirit-medium), to the processes of colonisation, and the effects of cattle lung-sickness which had decimated herds during 1855-56.
When the prophecy failed, the Xhosa initially blamed unbelievers (a small minority) and then turned on Nongqawuse, who was subsequently arrested by the British authorities and sent to Robben Island.