x1 reflects Roman culture/nation/geography/language/history in aspect x2 prior to any divisions. x1 pertains to the Roman city/city-state/kingdom/Republic/Empire (prior to division).
From a Roman citizen's point of view, emphasizes and centres on Rome (the city) itself - if applied to something outside of nearby Italy, such usage would always connote a directed relationship with Rome/Italy; modern usage is perhaps slightly freer. Culturally and in many ways socially, economically, etc., Eastern and Western Rome were quite intricately related and interconnected- and similar- at first; usage of this word within a context of the divisions would emphasize its umbrella/general scope (possibly for the sake of contrast as much as for displaying similarity or treating everyone with equal footing/care/at once). See also: latmo, latmrbizanto, latmrstici, latmrfriko, xelso, kartapuno