In what period and at what place was this first begun, and why was this taken up? From where did Kṛṣṇa-dvaipāyana Vyāsa, the great sage, get the inspiration to compile this literature?
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
कस्मिन् युगे प्रवृत्तेयं स्थाने वा केन हेतुना । कुतः सञ्चोदितः कृष्णः कृतवान् संहितां मुनिः
kasmin yuge pravṛtteyaṃ sthāne vā kena hetunā | kutaḥ sañcoditaḥ kṛṣṇaḥ kṛtavān saṃhitāṃ muniḥ
SB 1.4.3