Irene was overthrown and exiled by Nikephoros I and henceforth there were two Roman Emperors

This can be seen as symbolic of the papacy turning away from the declining Byzantine Empire towards the new power of Carolingian Francia. Charlemagne adopted the formula Renovatio imperii Romanorum ("renewal of the Roman Empire"). In 802, Irene was overthrown and exiled by Nikephoros I and henceforth there were two Roman Emperors.