in 1820 muhammad ali gave orders to commence the conquest of eastern libya. he first sent an expedition westward (feb. 1820) which conquered and annexed the siwa oasis. ali's intentions for sudan was to extend his rule southward, to capture the valuable caravan trade bound for the red sea, and to secure the rich gold mines which he believed to exist in sennar. he also saw in the campaign a means of getting rid of his disaffected troops, and of obtaining a sufficient number of captives to form the nucleus of the new army.