Rome was the sole political capital until AD ؛286
There were several political centres during the Tetrarchy while Rome continued to be the nominal, cultural, and ideological capital. Constantine re-founded and established the city of Constantinople as the new capital of the empire in 330. Mediolanum (Milan) was its western counterpart during the increasingly frequent East/West divisions. The western imperial court was later relocated to Ravenna.
الرومان هم شعب استقر فى وسط شبه الجزيرة الايطالية ابتداء من القرن الاتناشر قبل الميلاد واسسو مدينة روما القديمة و اسسو دولة سيطرت على شبه الجزيرة الايطالية و اتوسعت الدولة الرومانية وسيطرت على معظم العالم القديم .
↑Since classical and modern concepts of state do not coincide, other possibilities include Res publica Romana, Imperium Romanum or Romanorum (also in Greek: Βασιλείᾱ τῶν Ῥωμαίων – Basileíā tôn Rhōmaíōn – ["Dominion (Literally 'kingdom') of the Romans"]) and Romania. Res publica, as a term denoting the Roman "commonwealth" in general, can refer to both the Republican and the Imperial era, while Imperium Romanum (or, sometimes, Romanorum) is used to refer to the territorial extent of Roman authority. Populus Romanus, "the Roman people", is often used for the Roman state dealing with other nations. The term Romania, initially a colloquial term for the empire's territory as well as the collectivity of its inhabitants, appears in Greek and Latin sources from the fourth century onward and was eventually carried over to the Byzantine Empire. (See Wolff, R.L. "Romania: The Latin Empire of Constantinople". In: Speculum, 23 (1948), pp. ١–34 (pp. ٢–٣).)