Livingstone and Kirk were both dedicated to the suppression of the slave trade in Africa, a cause championed by British liberals. It presented a political paradox. Slavery could only be stopped by military opposition to the slavers. If British forces did intervene, the government was accused of building a colonial empire. This contradiction brought down the second premiership of William Gladstone in 1885, when he did not go to the assistance of Charles George Gordon at Khartoum. The latter was attempting to defend the city against Muhammad Ahmad, slaver, and new Islamic messiah. Gordon was killed. The tide turned in Britain in favor of the empire. After the Battle of Omdurman, 1896, the region was brought into the empire as the Anglo-Egyptian Sudan.