Translatio imperii is a historiographical concept that originated from the Middle Ages, in which history is viewed as a linear succession of transfers of an imperium that invests supreme power in a singular ruler, an "emperor". The concept is closely linked to translatio studii. Both terms are thought to have their origins in the second chapter of the Book of Daniel in the Hebrew Bible.
Definition
describes the translatio imperii concept as "typical" for the Middle Ages for several reasons:
the idea of linearity of time and history was typical for the Middle Ages;
the translatio imperii idea typically also neglected simultaneous developments in other parts of the world ;
the translatio imperii idea didn't separate "divine" history from the history of "worldly power": medieval Europeans considered divine and material things as part of the same continuum, which was their reality. Also the causality of one reign necessarily leading to its successor was often detailed by the medieval chroniclers, and is seen as a typical medieval approach.
Each medieval author described the translatio imperii as a succession leaving the supreme power in the hands of the monarch ruling the region of the author's provenance:
Medieval and Renaissance authors often linked this transfer of power by genealogically attaching a ruling family to an ancient Greek or Trojan hero; this schema was modeled on Virgil's use of Aeneas as progenitor of the city of Rome in his Aeneid. Continuing with this tradition, the twelfth-century Anglo-Norman authors Geoffrey of Monmouth and Wace linked the founding of Britain to the arrival of Brutus of Troy, son of Aeneas. In a similar way, the French Renaissance author Jean Lemaire de Belges linked the founding of Celtic Gaul to the arrival of the Trojan Francus, the son of Hector; and of Celtic Germany to the arrival of Bavo, the cousin of Priam; in this way he established an illustrious genealogy for Pepin and Charlemagne.
As early as 781, Irene began to seek a closer relationship with the Carolingian dynasty and the Papacy. She negotiated a marriage between her son Constantine and Rotrude, a daughter of the ruling Frankish king, Charlemagne. Irene went as far as to send an official to instruct the Frankish princess in Greek; however, Irene herself broke off the engagement in 787, against her son's wishes.
As Constantine VI approached maturity, the relationship between mother/regent and son/emperor was increasingly strained. In 797 Irene deposed her son, with his eyes being mutilated, who died soon afterwards.
Some Western authorities considered the Byzantine throne, now occupied by a woman, to be vacant and instead recognized that Charlemagne, who controlled Italy and much part of the former Western Roman Empire, had a valid claim to the imperial title. Pope Leo III, crowned Charlemagne as Roman Emperor in 800, an act not recognized by the Byzantine Empire.
Irene is said to have endeavored to negotiate a marriage between herself and Charlemagne, but according to Theophanes the Confessor, who alone mentioned it, the scheme was frustrated by Aetios, one of her favorites.
In 802, Empress Irene was deposed by a conspiracy and replaced by Nikephoros I. She was exiled and died the following year.
Recognition of Charlemagne as Emperor in 812 by Emperor Michael I Rangabe of the Byzantine Empire, after he reopened negotiations with the Franks. In exchange for that recognition, Venice was returned to the Byzantine Empire.
On April 972 14, Otto I married is son and heir Otto II to the Byzantine Princess Theophanu. Through their wedding contract, Otto was recognzied Emperor in the West, a title Theopanu was to assume together with her husband through the Consortium imperii after his death.
