Hello everyone!
Ven. @sujato has written repeatedly (here and here) about the four groups of Buddhist (Maha)nikayas: Sarvastivāda, Mahāsāṃghika, Pudgalavada, and Theriya (*Vibhajjavāda). As far as I know, this classification is quite late. It is found, for example, in the I Ching (7th century), the Hevajra Tantra (late 8th century), and “Bhikṣuvarṣāgraprcchā” by Padmākaraghoṣa (10th–11th centuries). This scheme is likely implied in the commentary to the Digha Nikaya:
Therānaṃ mahākassapādīnaṃ vaṃso paveṇī anvayo etassāti theravaṃsanvayo, tena; catumahānikāyesu theriyenāti attho.
My question: are there earlier references to this classification? What is the earliest reference we know of?
With mettā.
P.S. My English is poor. I hope I was able to explain the question clearly.