The development of Quranic exegesis (tafsir) has undergone significant historical phases that form the foundation of Islamic intellectual tradition. This article examines two pivotal periods in the history of tafsir: the formative/classical period and the affirmative/medieval period. Using a historical-descriptive approach through library research, this study analyzes the sources and methods, characteristics, and key exegetes (mufassirin) of each period. The formative/classical period, spanning from the era of the Prophet Muhammad to the tabi'in generation, was characterized by reliance on riwayah-based interpretation (bil-ma'tsur), oral transmission, and the authority of prophetic traditions and companions' opinions. The affirmative/medieval period witnessed a significant expansion in methodology and thematic corak, integrating disciplines such as jurisprudence (fiqh), theology (kalam), philosophy, and Sufism into Quranic interpretation. Prominent figures such as al-Tabari, al-Zamakhshari, al-Razi, Ibn Kathir, and al-Qurtubi produced monumental works during the latter period. The study concludes that both periods represent a continuum of scholarly endeavor, with the formative period establishing normative foundations and the medieval period consolidating and diversifying the exegetical tradition