In the spring of 1885 Henry Rider Haggard, then the author of a book about Zululand and an ineffectual novel called Dawn, was travelling up to Liverpool Street Station from his home in Norfolk. Opposite him in the train compartment sat his elder brother John, a former naval officer. In her biography of Rider, Lilias Haggard, the writer 's daughter, catches the swaggering tone of their conversation: ‘they started discussing Treasure Island. Rider said he didn't think that it was so very remarkable, whereupon his brother replied, rather indignantly: “Well, I'd like to see you write anything half as good – bet you a bob you can't.” “Done.” said Rider …’.

It is much in the spirit of Haggard's fiction that he should have embarked on the writing of travel romance in response to a wager. As a matter of fact, he respected Stevenson's work deeply, though typically his reaction was to attempt to beat the Scottish author at his own game. In his autobiography The Days of my Life he makes this spirit of competition perfectly clear. He also suggests that his plan to outdo Stevenson had been in his mind for some time. About 1882 he confessed, ‘I read in one of the weekly papers a notice of Stevenson's Treasure Island so laudatory that I procured and studied that work, and was impelled by its perusal to write a book for boys‘(DML i. 230). The result was King Solomon's Mines.

In setting off into this unknown literary territory, Haggard possessed one supreme advantage. Ten years previously, despairing of Rider's poor performance at school, his father had obtained for him a post on the staff of Sir Henry Bulwer, Lieutenant-Governor of the province of Natal in South Africa. In Natal, Rider had discovered a new aptitude for work; he had impressed his superiors, learned Zulu, and helped to investigate a spate of witch persecutions then afflicting the province. Soon he had attracted the attention of the Secretary for Native Affairs, Sir Theophilus Shepstone, whom he accompanied on an expedition to annexe the Boer Transvaal in 1877.