In the article I argue that the post-Vedic grammatical scholarship that culminated in the composition of Pāṇini’s Aṣṭādhyāyī was made possible by writing, which had been introduced in Gandhāra in the wake of the Achaemenids’ conquest of north-west India in the late 6th century BCE. I present and discuss some of the structural and terminological features of Pāṇini’s Aṣṭādhyāyī which suggest that it originated in a literate milieu. Moreover, I argue that Pāṇinian grammar constituted an epistemic rupture in the culture of ancient India as it marked a major shift towards the secularisation of knowledge. Perhaps of even greater historical consequence is the fact that Pāṇini’s early grammatisation of Sanskrit was arguably one of the key factors in the emergence of Sanskrit as the dominant language of culture in South Asia and beyond for centuries to come.