Help with a translation

[Titvs Statilivs Castvs]

"Here under are the shown men of the Duke of Arabia"

It's actually the Dux who's the vir spectabilis, so the text runs:
"Under the control of the most admirable Duke of Arabia: ..."
(If I remember correctly, this is not idle flattery -- there were recognised grades of viri.)

And, correct me if I'm wrong, Dux means "Leader" or "General", not Duke. Knew the Romans such a title? I think not.