Da'a'im al-Islam was written to govern a state, not only a congregation. Al-Qadi al-Numan compiled it in the tenth century CE while serving as chief judge under the Fatimid Caliphate, the Ismaili Shia dynasty that ruled Egypt and, at its height, much of North Africa and parts of the Levant from its capital in Cairo, and the book was adopted as the empire's official legal reference. It is organized in two volumes, one covering acts of worship, ritual purity, prayer, fasting and pilgrimage, the other covering social transactions, marriage, inheritance, commerce and criminal law, a structure familiar from Sunni legal manuals of the period.
What sets it apart is its chain of authority: where Sunni hadith collections trace rulings back through a wide circle of the Prophet's companions, and Twelver Shia collections trace them through a line of twelve Imams, Da'a'im al-Islam traces its hadith specifically through Ali and the line of Ismaili Imams descended from him, reflecting the Fatimid state's own claim to legitimate religious and political authority resting in that line. Al-Numan held the position of chief qadi under three successive Fatimid caliphs and wrote extensively beyond Da'a'im al-Islam itself, but it was this two-volume code, rather than his other juristic and polemical writing, that the state adopted as its working legal reference.