After Jarasandha’s death, the Pandavas launched campaigns to establish their sovereignty over kingdoms across the Indian subcontinent. There is irony here, as they had set out on the same path of subjugating other kings and extracting tributes just as Jarasandha, whom Krishna had chastised for his treatment of other kings. But this irony is unrecognised in the epic, and the basic assumption is that, backed by Krishna, the Pandavas were seen as the righteous ones.
Nevertheless, their imperial aspirations and the battles required to sustain them, dispel notions that the their kingdom was a peace-loving one.King Yudhistira himself doesn’t step out of the capital; it is his four brothers who lead armies in four directions. Again, the irony implicit in the fact that someone known as ‘Dharmaraja’, or the king of ethics and good conduct, is more often than not a man who drives his aspirations by proxy and is otherwise a model only for indecision (recall his dithering at the prospect of killing Jarasandha) and inaction (he hasn’t engaged in any battle himself), is lost not only on Yudhistira’s brothers, but the epic itself.
Arjun goes north and subjugates every kingdom in his path, eventually reaching the inner sanctums of the high Himalayas and knocking (literally) on the doors of the divine kingdoms there. Bhima, who goes east, is similarly successful, but his case is more interesting, for he encounters Karna, the ruler of Anga (present-day Bengal). There is no mention of a battle between these two great warriors, but it is given that Karna accepted subjugation and gave tribute to Bhima. This is mind-boggling, as Karna’s allegiances were expected to lie with the kingdom of Hastinapura, run by Duryodhana, rather than the kingdom of Indraprastha.
It is likely that the Pandava campaigns of conquest were being run in the joint name of the Kuru family, a name that included the Kauravas. If true, this would have also helped avoid the awkward scenario of having to ask Duryodhana to pay a tribute to Yudhistira. As it happens, the Digvijaya Parva — chronicling the conquests of the Pandavas — names dozens of kingdoms but makes no mention of Hastinapura.
Going westward, Nakul has the easiest pass among the brothers, for most of the kingdoms there have been previously conquered by Krishna and accept subjugation readily. It is Sahadeva, who goes southward, who faces the most trouble. On the outskirts of the city of Mahishmati, a forest fire engulfs his army and causes extensive damage. Sahadeva learns that the god of fire, Agni, had pledged to protect Mahishmati (as retribution for having congressed with king Nila’s daughter in the guise of a brahman). Nakul genuflects before Agni, and requests his help in ensuring the success of Yudhistira’s ‘sacrifice’. The peace between king Nila and Sahadeva is eventually brokered by Agni himself, and the Mahishmati king agrees to pay tribute to the name of Yudhistira.After the four campaigns are concluded, the ground is set for the rajasuya sacrifice.