During the Khedivial period, dissent had spread due to harsh taxes imposed on most activities. Taxation on irrigation wells and farming lands were so high most farmers abandoned their farms and livestock. During the 1870s, European initiatives against the slave trade had an adverse impact on the economy of northern Sudan, precipitating the rise of Mahdist forces. Muhammad Ahmad ibn Abd Allah, the ''Mahdi'' (Guided One), offered to the ''ansars'' (his followers) and those who surrendered to him a choice between adopting Islam or being killed. The Mahdiyah (Mahdist regime) imposed traditional Sharia Islamic laws.