Vishnupurana 3.2.p12

3.2.p12

At the end of every four Yugas the Vedas disappear. And the seven Rishis descending on the earth again establish them. In every Krita age the presiding Manu becomes the legislator and during the Manwantaras the celestials of the various classes receive sacrifices. And those born in the race of Manus lord over the earth for that period. In every Manwantara, the Manu, the seven Rishis, the king of the gods and the sons of the Manu rule over the earth. In this wise, O Brahmin, fourteen Manwantaras constitute a Kalpa. And it is succeeded by a night of similar duration.