Mahāparinirvāṇasūtra (which Michael Radich dates as early as the 2nd Century) mentions tathāgathagarbha and used the term ātman to describe buddha-nature.
Tathāgatagarbhasūtra (as dated by Michael Zimmermann) and other scriptures later considered as sūtras teaching tathāgathagarbha were circulating and promoted the concept of buddha-nature.
Nāgārjuna wrote Dharmadhātustava and praised the sphere of reality as the basis of saṃsāra and nirvāṇa. He called it 'the element' and 'luminous mind' and claimed emptiness does not negate this nature.
Śrīmālādevīsiṃhanādanirdeśa (which may have been circulating as one of the most influential sūtras on buddha-nature) is said to have been translated into Chinese by Seng Fani. It claims buddha-nature 'is empty of adventitious stains but not empty of its limitless inseparable qualities'.
Mahābherīsūtra (which was translated into Chinese by Guṇabhadra) equates buddha-nature with dharmakāya. Anūnatvāpūrṇatvanirdeśaparivarta (which Jonathan Silk dates at least before the earliest 5th century) mentions how sentient beings, bodhisattvas and buddhas are three phase of the buddha-nature being impure, partially obscured and fully pure.
