the subtitle should perhaps read 'Rome’s border walls coincided with the beginning of its end' or similar; the article doesn't really argue that the walls cause

the subtitle should perhaps read 'Rome’s border walls coincided with the beginning of its end' or similar; the article doesn't really argue that the walls caused the downfall, more documenting the associated history for whatever it's worth the title is 'Roman Frontiers', the HN title is the subtitle