(fl. 4th century BCE [1] [2] ). He is known for his Sanskrit grammar, particularly for his formulation of the 3,959 rules [2] of Sanskrit morphology in the grammar known as Ashtadhyayi ( अष्टाध्यायी Aṣṭādhyāyī , meaning "eight chapters"), the foundational text of the grammatical branch of the Vedanga , the