Nimbarkacharya was the principal teacher—acharya—in the Kumara sampradaya, one of the four main lines of Vaishnava teachers and disciples. He appeared in South India, in Mungera-patana. His Vedanta-sutra commentary—Parijata-saurabha-bhasya—establishes the doctrine that the Absolute Truth includes both oneness and variety (known as Dwaitadwaita-vada). He preached Krishna consciousness about 300 years before the advent of Sri Chaitanya Mahaprabhu.
Image of Nimbarkacharya courtesy of ExoticIndiaArt.com