The title of all Emperors listed preceding Heraclius was officially Augustus, although various other titles such as Dominus were used as well. For official purposes, their names were preceded by Imperator Caesar and followed by Augustus. Following Heraclius, the title commonly became the Greek Basileus (Gr. Βασιλεύς), which had formerly meant generally "king", "sovereign" but now was used in place of Imperator. Following the establishment of a rival Empire in Western Europe (the Holy Roman Empire), the title Autokrator (Gr. Αυτοκράτωρ) was also increasingly used. Foreign kings were now titled by the neologism Regas (Gr. Ρήγας, from the Lat. "Rex") or by another generic term Archon (Gr. Άρχων, "ruler"). In the later centuries of the Empire, the emperor could be often referred to by Western Christians as the "Emperor of the Greeks," though they still considered themselves "Roman" Emperors. Towards the end of the Empire, they referred to themselves as "[Emperor's name] in Christ, true Emperor and Autocrat of the Romans."
