Mbh 1.94.4c

And Riksha begat Samvarana, the perpetuator of the royal line. And, O king, it hath been heard by us that while Samvarana, the son of Riksha, was ruling the earth, there happened a great loss of people from famine, pestilence, drought, and disease. And the Bharata princes were beaten by the troops of enemies. And the Panchalas setting out to invade the whole earth with their four kinds of troops soon brought the whole earth under their sway. And with their ten Akshauhinis the king of the Panchalas defeated the Bharata prince. Samvarana then with his wife and ministers, sons and relatives, fled in fear, and took shelter in the forest on the banks of the Sindhu extending to the foot of the mountains. There the Bharatas lived for a full thousand years, within their fort. And after they had lived there a thousand years, one day the illustrious Rishi Vasishtha approached the exiled Bharatas, who, on going out, saluted the Rishi and worshipped him by the offer of Arghya. And entertaining him with reverence, they represented everything unto that illustrious Rishi. And after he was seated on his seat, the king himself approached the Rishi and addressed him, saying, ‘Be thou our priest, O illustrious one! We will endeavour to regain our kingdom.’ And Vasishtha answered the Bharatas by saying, ‘Om’ (the sign of consent). It hath been heard by us that Vasishtha then installed the Bharata prince in the sovereignty of all the Kshatriyas on earth, making by virtue of his Mantras this descendant of Puru the veritable horns of the wild bull or the tusks of the wild elephants. And the king retook the capital that had been taken away from him and once more made all monarchs pay tribute to him. The powerful Samvarana, thus installed once more in the actual sovereignty of the whole earth, performed many sacrifices at which the presents to the Brahmanas were great.