Ante-Nicene Fathers, Vol VIII:
Pseudo-Clementine Literature.: Chapter XXXI

Chapter XXXI.—World After the Flood.

“In the eighteenth generation walled cities were built, armies were organized and armed, judges and laws were sanctioned, temples were built, and the princes of nations were adored as gods.  In the nineteenth generation the descendants of him who had been cursed after the flood, going beyond their proper bounds which they had obtained by lot in the western regions, drove into the eastern lands those who had obtained the middle portion of the world, and pursued them as far as Persia, while themselves violently took possession of the country from which they expelled them.  In the twentieth generation a son for the first time died before his father, 553 on account of an incestuous crime.”

Footnotes

Gen. xi. 28.