Over the next 1500 years, Arrakis (now called Rakis) is returned to a desert by the thriving sandworm cycle. Bene Gesserit Mother Superior Taraza becomes aware in Heretics of Dune that humanity is being limited by the prescient dream of Leto, and controlled by him through his worm remnants. She engineers the destruction of Rakis by the Honored Matres to free humanity, leaving one remaining worm to start the cycle anew. Taraza is killed; her successor Darwi Odrade takes the worm to Chapterhouse. She submerges it in a spice bath to generate sandtrout, with the goal of populating Chapterhouse, and later other planets, with new worms and infinite potential for gathering spice.
At that point, for nearly half-a-century, much of the southern African region had already been plunged into a massive process of monopoly capitalist-driven transformation. Rapid industrialisation, centred on the diamond fields around Kimberley and then the gold fields of the Witwatersrand, drew huge flows of private monopoly capital from the imperialist centres. There were major investments in mines, and also in rail and port infrastructure connecting the mining hinterland to the colonial ports. The Anglo-Boer war, the largest armed conflict of its time, forcibly consolidated disparate states, establishing a single geographical political entity, the Union of South Africa, under British imperial hegemony. In 1910, the Union of South Africa became a semi-independent British dominion under local white minority rule.