Rioters, footballers or Romans…they all were human and levels of aggressiveness varied somewhat from individual to individual with some slight variance in cultures, but if you look at primate troupes fighting, i expect that you won’t find that humans have evolved that much from when we stepped down from the trees. To say we cannot get inside the mindset of Romans because we evolved away from the militarism of the Victorian period is a gross oversimplification. (which really hasn’t evolved away either…plenty of “alpha male aggressiveness” in contemporary British, German and American society. The only factor that makes me think any culture might have valued their individual lives less is probably a concept of a paradise in the afterlife which was always a bit subject to doubt. Everyone still had only one go round with their own life, even if it was short, and relatively speaking its loss, was the greatest of sacrifices. Human behavior has always been subject to the same hierarchy of basic needs. that never changes.