Brahmā's Son and His Pupil

Ṛbhu was a son of Brahmā, the highest one, and he knew the truth of things by his own nature. His pupil was Nidāgha, a son of Pulastya, and Ṛbhu gladly gave him all his knowledge. But Ṛbhu saw that Nidāgha had not grasped the heart of that knowledge, and had no settled sense that all is one.

On the bank of the river Devikā there was a city called Vīranagara, rich and lovely, founded by Pulastya. There, at the edge of its pleasant gardens, lived Nidāgha, Ṛbhu's pupil, who knew yoga.