Explanation: The Roman Empire had two prominent 'successors' after it fell - the Holy Roman Empire, and the Byzantine Empire.
The Holy Roman Empire was a continuation in name only - it was formed over 300 years after the fall of Rome, had no continuation of Roman institutions, and had its only real link in the approval of the Pope - who, in turn, only sought to legitimize the polity because the Byzantine Empire was being run by a woman at the time, and because the Byzantines didn't recognize the Pope's ultimate spiritual authority.
The Byzantine Empire was a continuation in more than name - the term 'Byzantine' is only a term of modern convenience. The Byzantines regarded themselves as simply the Roman Empire - 'Basileía Romaíon' ('The Roman Kingdom'). But even though there was technically unbroken continuity from the Eastern Roman Empire of Late Antiquity, the Byzantines had very little in common with the Roman Empire of old - regarding their rulers as monarchs, Latin as a 'barbarian tongue', Christianity as the main identifier of 'Romanness', violation of traditional Roman norms, and controlling only the old Greek portions of the former Roman Empire. In the European West, they were simply known as the Kingdom or Empire of the Greeks.
I only recognize ONE brutal pre-modern Imperial autocracy, and that is the Roman Empire of antiquity!