The earliest that I know of was the Roman Emperor Augustus, who passed quite a few laws to promote his idea of traditional Roman family life.

[Augustus] laid heavier assessment upon the unmarried men and upon the women without husbands, and on the other hand offered prizes for marriage and the begetting of children. And since among the nobility there were far more males than females, he allowed all who wished, except the senators, to marry freedwomen, and ordered that their offspring should be held legitimate.

Cassius Dio, 54.16

The Pater Familias in Rome