"Roaring Jake" Griffith and his son's movie, "Birth of a Nation."

Cinematographer Billy Bitzer and director/producer D.W. Griffith.

His dad’s nickname was “Roaring Jake” Griffith and boy, had he earned it.

A Mexican War veteran, Roaring Jake had been a frontier doctor, led a Kentucky wagon train across the Prairie, mined for California gold, and rescued hapless settlers from the snows of Donner’s Pass.

He had gotten sh…