The main exponent of the Kumara or Chatuhsana sampradaya (this knowledge was transmitted to the four Kumaras by the Hamsa avatara), who lived in the 13th century and propagated the doctrine called dvaita advaita, “simultaneous oneness and duality”.
Shri Nimbarkacharya is believed to be the incarnation of the Sudarshana Chakra (the Discus weapon of Krishna)
At the end of Treta Yuga, the Brahmanas, being afraid of the Asuras, prayed to Lord Hari. They also prayed to Brahma who himself prayed to Lord Hari again. Then the Lord summoned his own Sudarshana Chakra -a part of Himself- and commanded him to descend on earth to revive and teach the Vaishnava Dharma which was waning and which he could learn from Narada, and spread it all around.
The incarnation of the Sudarshana Chakra occurred, according to the Bhavishya Purana in the month of Kartika on the evening of the full moon in the year 3096 BCE. His mother, Jayanti and father, Aruna were Tailanga Brahmanas, who resided on the banks of the river Godavari at a place known as Telinga, the modern Vaidurya Pattanam in Andhra Pradesh.
He was named Niyamananda at birth. The region was famed for its scholarly learning, and by the age of 16, Niyamananda had mastered the Vedas and all related philosophical scripture.
With the permission of his parents, Niyamananda then embarked on a search of a true Guru. Upon reaching Govardhan in Mathura, Uttar Pradesh, he began practising penance under the shade of Neem trees.
It was here, performing tapasya in Nimba Grama, right in between Govardhana and Barsana, that he was visited by Brahma Ji, who recognised him as the incarnation of the Sudarshan Chakra and bestowed upon him the name Nimbarka.
He performed severe austerities and survived by drinking only a mouthful of bitter neem juice once a day.
Seeing his determination, Shri Narada Muni blessed him and initiated him into the Hamsa Sampradaya of Vaisnava Dharma. The great sage Narada gave him initiation according to Vaishnava rites, and bestowed him the Shalagrama Deity known as Shri Sarveshvara (the Lord of All). Continuing, Narada renamed him Haripriya (one dear to the Lord).
Pleased with his penance, the Sage Narada blessed him with the knowledge of true Vedanta, the doctrine of Dvaitadvaita – or unity in duality. After this, Niyamananda begged Narada to accept him as a disciple.
He then instructed Niyamananda on the Gopala Mantra of the Gopalatapini Upanishad.
Once completed, the Sage Narada instructed him to practise further penance with that Mantra and all will be revealed before leaving.
In the ritual recitation and meditation upon that mantra, the Lord revealed Himself as Shri Radha-Krishna. Niyamananda worshipped them, and was blessed with the recollection of his former glory as the Sudarshana Chakra of that very Lord. The Lord instructed him to teach this philosophy to all, and departed.
When the Lord revealed themselves, they reminded him of his eternal position as a Nitya-Mukta Vaisnava, who was the combined partial incarnation of the Lord – Shri Radha Rani’s expansion as Rangadevi and Bhagavan’s expansion as Aniruddha Bhagavan came together in this form of Nimbarka.
Narada Muni mentions Nimbarkacharya Ji in his Narada Bhakti Sutra as one of the great Acharyas of devotion. Nimbarka Bhagavan, on the direction of Narada Muni, composed his treatises on the Upanishads, Geeta and the Brahma Sutras and daily pracised his recitation of Gopal Mantra and worship of Shri Sarveshwar Bhagavan which resulted in the Supreme Vision of Shri Shri Radha Madhava.