Formless Attainments

Majjhima Nikaya MN26. Ariyapariyesanaa Sutta: The Noble Search (ปาสราสิสูตร)
(also known as the Paasaraasi Sutta: The Heap of Snares - the Thai translation has this second title)

The Lord Buddha gives the bhikkhus gives a summary of his search for enlightenment. The sutta covers the then Bodhisatta's training period with two eminent teachers. Aa.laara Kaalaama and Uddaka Raamaputta.

MN26.15 states that "Aa.laara Kaalaama has faith, energy, mindfulness, concentration, and wisdom..." the five controlling faculties indriya and five powers bala.
MN26.16 states that "(Uddaka) Raama(putta) has faith, energy, mindfulness, concentration, and wisdom..." the five controlling faculties indriya and five powers bala.

Aa.laara Kaalaama (AK) and Uddaka Raamaputta (UR) both died before Lord Buddha rolled the Wheel of the Dhamma and started the current dispensation. AK and UR both attained formless attainments (jhaana) under the Brahmin system (? or itinerant yogi - mendicant system) before Lord Buddha taught it. AK reached base of nothingness which is the third formless attainment and UR reached the base of neither perception-nor-non-perception which is the fourth formless attainment. Both teachers had large followings. I'm not sure if the followers appointed new leaders after they each passed away? (MN26.15-16) "I soon quickly learned that Dhamma. As far as mere lip-reciting and rehearsal of his teaching went, I could speak with knowledge and assurance, and I claimed, 'I know and see'--and there were others who did likewise."

The teachings of AK and UR must have been similar with each other, perhaps based on some common Brahmin roots. Their teaching probably contained some worship of Brahma deity and or a belief in an eternal soul-like identity which persists life after life until union with the Brahma diety. Buddhists consider this as wrong view that would prevent AK and UR from seeing the three general characteristics and Nibbaana. I have not found any reference to the former followers of AK and UR later joining the Buddhist Sangha.