>>512276064 (OP)
>the State
Constantine moves the capital to Byzantion, the empire loses its Western half that includes its Former capital, then it loses its remaining Southern half to the Arabs, and one day the empire gets usurped by Turks and replaced 1-to-1 with a Turkish empire, whose successor is the Turkish Republic.
>the Race
Ancient Rome creates Latin Europe that includes Italy, Gaul/France, and Spain/Iberia, who go on to produce the Spanish, Portuguese, and French empires, with Spain having the biggest empire and doing most to spread Roman blood, but France becoming the ultimate leader of Latin Europe and the Roman People as of Napoleon.
>the Culture
Roman culture is usurped and overhauled by the Catholic Church, that passes on Rome's dying empire to the Greeks and latches on to the Germanic people that take over the Italian peninsula, spiritually conquering those who conquered them temporally, sponsoring Francia/HRR for a whole thousand years, sponsoring the Spaniards to reconquer Iberia and conquer the Americas, sponsoring Napoleon to re-monarchize France and retire the HRR, and sponsoring Mussolini to create the Vatican City that today serves as the state and headquarters of the Roman Catholic Church.