Jubilees 4:9

And Cain took Âwân his sister to be his wife and she bare him Enoch at the close of the fourth jubilee. [190-196 A.M.] And in the first year of the first week of the fifth jubilee, [197 A.M.] houses were built on the earth, and Cain built a city, and called its name after the name of his son Enoch.