ruling members of the Muhammad Ali dynasty seeking to preserve and extend the "unity of the Nile Valley". This policy was expanded and intensified most notably by Muhammad Ali's grandson, Ismail Pasha, under whose reign most of the remainder of modern-day Sudan, and South Sudan was conquered. British involvement With the opening of the Suez Canal in 1869, Egypt and Sudan's economic and strategic importance increased enormously, attracting the imperial attentions of the Great Powers, particularly the United Kingdom. Ten years later in 1879, the immense foreign debt of Ismail Pasha's government served as the pretext for the Great Powers to force his abdication and replacement by his son Tewfik Pasha. The manner of Tewfik's ascension at the hands of foreign powers greatly angered Egyptian and Sudanese nationalists who resented the ever-increasing influence of European governments and merchants in the affairs of the country. The situation was compounded by Tewfik's perceived corruption and mismanagement, ultimately culminating in the Orabi Revolt led by the nationalist head of the army, Ahmed Orabi. With the survival of his throne in dire jeopardy, Tewfik appealed for British assistance. In 1882, at Tewfik's invitation, the British bombarded Alexandria, Egypt's and Sudan's primary seaport, and subsequently invaded the country. British forces overthrew the Orabi government in Cairo, and proceeded to occupy the rest of Egypt and Sudan in 1882. Though officially the authority of Tewfik had been restored, in reality the British largely took control of Egyptian and Sudanese affairs. Mahdist revolt Tewfik's acquiescence to British occupation as the price for securing the monarchy was deeply detested by many throughout Egypt and Sudan. With the bulk of British forces stationed in northern Egypt, protecting Cairo, Alexandria, and the Suez Canal, opposition to Tewfik and his European protectors was stymied in Egypt. In contrast, the British military presence in Sudan was comparatively limited, and eventually revolt broke out. The rebellion in Sudan, led by the Sudanese religious leader Muhammad ibn Abdalla, the self-proclaimed Mahdi (Guided One), was both political and religious. Abdalla wished not only to expel the British, but to overthrow the monarchy, viewed as secular and Western-leaning, and replace it with what he viewed as a pure Islamic government. Whilst primarily a Sudanese figure, Abdalla even attracted the support of some Egyptian nationalists, and caught Tewfik and the British off-guard. The revolt culminated in the fall of Khartoum, and the death of the British General