The Great Epic of the Bhārata dynasty 1.2.9

1.2.9

antare caiva saṃprāpte kalidvāparayorabhūt |
samantapañcake yuddhaṃ kurupāṇḍavasenayoḥ || 9 ||

"Rama said, 'If, O fathers, ye are favourably disposed towards me, the boon I ask is that I may be absolved from the sins born of my having annihilated the Kshatriyas in anger, and that the lakes I have formed may become famous in the world as holy shrines.' The Pitris then said, 'So shall it be. But be thou pacified.' And Rama was pacified accordingly. The region that lieth near unto those lakes of gory water, from that time hath been celebrated as Samanta-panchaka the holy. The wise have declared that every country should be distinguished by a name significant of some circumstance which may have rendered it famous. In the interval between the Dwapara and the Kali Yugas there happened at Samanta-panchaka the encounter between the armies of the Kauravas and the Pandavas. In that holy region, without ruggedness of any kind, were assembled eighteen Akshauhinis of soldiers eager for battle. And, O Brahmanas, having come thereto, they were all slain on the spot. Thus the name of that region, O Brahmanas, hath been explained, and the country described to you as a sacred and delightful one. I have mentioned the whole of what relateth to it as the region is celebrated throughout the three worlds.'