Prāgjyotisha (also called Prāgjyotishapura) was the great fortified city of the far east. It was the capital of the asura king Narakāsura and, after his death, of Bhagadatta. It was one of the most strongly defended cities in the three worlds. The city is linked with the region of present-day Assam (Kāmarūpa, or Prāgjyotisha in ancient geography) and with the basin of the Brahmaputra river, called Lauhitya.

Where it lay

Prāgjyotisha lay in the far eastern reaches of Bhārata, beyond the Lauhitya (Brahmaputra) region, where the land borders the forests and hills of the north-east. The name is read as “the city of the eastern star or light”, or “the eastern astral city”. Its place is linked with Kāmarūpa, the ancient name of the Assam region. In the geography of the Mahābhārata it was counted among the boundary cities of the known world.

Bhagadatta took over the kingdom after Narakāsura’s death. He ruled the eastern lands in the time of the Mahābhārata. He was one of the most formidable warriors Arjuna met during his digvijaya (conquest of the quarters) in the north-east.

The defences of Narakāsura

Under Narakāsura, Prāgjyotisha could not be taken by ordinary means. Its defences were:

The six thousand pāśas of Mura. These were magical binding-ropes that surrounded the city and could hold whole armies helpless.
Mountain barriers, both natural and built up by hand.
Moats, filled with asura sentinels.
Asura commanders. Mura, Niśumbha (not the Niśumbha of the Devī Māhātmya), Hayagrīva and Pāñcajana each commanded a part of the defence.
Asura forces in the thousands.

Only Bhagavān Kṛshṇa, coming down on Garuḍa with Satyabhāmā, could break through these defences.

The campaign against Narakāsura

Bhagavān Kṛshṇa broke through the outer defences, killed Mura and his five sons, and defeated the other commanders. At last he met Narakāsura himself in single combat. The campaign brought back Aditi’s stolen kuṇḍalas (earrings), freed sixteen thousand captive women, and restored the divine treasures that Narakāsura had hoarded. After the battle, Bhagavān Kṛshṇa made Narakāsura’s son Bhagadatta king of Prāgjyotisha, so that the kingdom would have a lawful ruler.

Sources

Mahābhārata, Sabhā Parva, dākshiṇātya prati (southern recension), Chapter 38
Hari Vamśa Purāṇa, Vishṇu Parva, Chapters 65–66