You could almost say Alexander the Great, 'liberating' Egypt from the Persian yoke and spreading Hellenism, although that is somewhat contestable, and some say, complete bullshit. In any case the question isn't what he did, but said. Obviously the rhetoric of war has changed a lot through history. The idea of specifically 'humanitarian' intervention is very new - post UN - although colonial activity in the nineteenth century claimed a civilising mission... The project of bringing Christianity to the heathens in the new world has a link here too, although clearly this is a little different too. I think the main point is, as far as I know, in all recorded history, there has to my knowledge NEVER been a purely 'offensive' war. Every single one has been presented as defensive or as justified in other ways.