SB 12.7.16
rajñam brahma-prasutanam
vamsas trai-kaliko ’nvayah
vamsanucaritam tesam
vrttam vamsa-dharas ca ye
Translation:
Dynasties are lines of kings originating with Lord Brahma and extending continuously through past, present and future. The accounts of such dynasties, especially of their most prominent members, constitute the subject of dynastic history.