The oldest account of the Nagars is given in the Nagar Khand, a part of the Skanda Purana.
The eminent historian D. R. Bhandarkar was the first to point out that the surnames used by the Nagar Brahmins in the recent past are amongst the surnames of Brahmins in whose favour the Kings made grants, as found in early inscriptions between the 6th and 8th centuries AD. Dr. Bhandarkar has shown that the Sapadalaksha Brahmins were the same as the Nagar Brahmins, who were undoubtedly of Alpine origin. Alpine Aryans are believed to have entered India as part of Aryan immigration during the third millennium BC. It has been suggested that the Nagar Brahmins along with the present-day Bengali Kayasthas are amongst the purest forms of this type; they were originally the Brahmin priests of the Alpines, as evident from several early inscriptions, and that probably explains their comparative pure state till now.