i need to know the name of a film

[suki75]

it's a sci-fi movie which this army of roman type people wipe out the planet and blow it up with big square space ships but there is one man who is half like them who saves this planet and becomes king of these people.any ideas of what film is called and who is in it?.please can someone help i'm going mad trying to find out!

[Mattk]

chronicles of riddick ?

[Aquariel]

Stargate ?