An incomplete revolutionary victory prevents a clean break from doctrine

Evidence

The same problem arose for the victorious Fatimids, but in a more complex form, since their victory was slower and incomplete. Sixty years and three un­ successful attempts intervened between the establishment of the Fatimid Ca­ liphate in Tunisia and its extension to Egypt. The further conquest of the Islamic East was never accomplished. The Fatimid Caliphs, like the first Abbasids, found that the views and wishes of the missionaries did not always accord with the needs of the state, and from time to time, both in the Tunisian and in the Egyptian phases, there are indications of disagreement and repression within the Isma ili fold—even of secession. But the Fatimids, unlike the Abbasids, could not afford to break completely with the mission, since there was still important work for the mission to do. The aim of the Fatimids, at least until al-Mustansfiir, was to overthrow and supersede the Abbasid Caliphate—to establish their own Imamate and their Isma ili faith in the whole world of Islam. — Bernard Lewis, From Babel to Dragomans, 382

Categorization

• XREF: Contrasts with the Abbasid case at 381 to sketch a continuum: degree of revolutionary success determines how far a regime can jettison its founding ideology.