This chapter is centered on the biography of Musa al-Ka?im (d. 183/799). Sunni historical chronicles utilized al-Ka?im to highlight the deterioration of the relationship between the ‘Abbasids and the ‘Alids. Many chroniclers integrated these familial tensions into a broad narrative detailing the rise and fall of ‘Abbasid power. Sunni biographical works, by contrast, included al-Ka?im in a wider community of pious scholars, focusing on his generosity and piety. Zaydi authors focused almost exclusively on court and caliphal politics, citing al-Ka?im’s refusal to support the rebellion at Fakhkh to compare him unfavorably with Ya?ya b. ‘Abd Allah. Twelver authors appropriated malleable narrative elements to craft interpretive frameworks that reflected the community’s political and social conditions. Overall, the chapter highlights the fact that all Muslim historians operated within the presuppositions of rhetoricized historiography with no real methodological difference between those of Sunni and Shi‘i backgrounds.