1898 envelope endorsed at the top 'Nile Field Force' to London bearing a 1p cancelled HALFA 23 VI 98. Alexandrie 1 VII 98 and London JY 7 98 cancels are on the back. In 1898 an expedition under General Kitchener was organised to defeat the Mahdi once and for all. The force consisted of 8,200 British soldiers and 17,600 Egyptian and Sudanese soldiers commanded by British officers. The Mahdist forces (sometimes called the Dervishes) were more numerous, numbering more than 60,000 warriors, but lacked modern weapons. They were defeated at the battle of Atbara in April 1898 and the Anglo-Egyptian forces then went on to capture Omdurman, the Mahdist capital in September 1898. This cover was sent during this campaign.