I take it you have no history books that cover this period?
This took place after Dingane attacked the Boer voortrekkers at Weenen.
Dingane's forces attacked a British force made up of twenty British settlers and seven hundred loyal Africans on the Tugela River on 17th April 1838. Only four of the Britons survived. The Zulus then attacked Port Natal and the inhabitants were forced to take refuge on-board ships in the harbour, whilst the settlement was put to the torch. Amongst those refugees was the infant John Dunn.