The Donation of Constantine (Latin: Donatio Constantini) is a forged Roman imperial decree by which the 4th-century emperor Constantine the Great supposedly transferred authority over Rome and the western part of the Roman Empire to the Pope. Composed probably in the 8th century, it was used, especially in the 13th century, in support of claims of political authority by the papacy. Lorenzo Valla, an Italian Catholic priest and Renaissance humanist, is credited with first exposing the forgery with solid philological arguments in 1439-1440, although the document's authenticity had been repeatedly contested since 1001. In many of the existing manuscripts (handwritten copies of the document), including the oldest one, the document bears the title Constitutum domini Constantini imperatoris. The Donation of Constantine was included in the 9th-century Pseudo-Isidorean Decretals collection.
After the fall of Rome, Charlemagne, also called Charles I or Charles the Great, from 768 as king of the Franks founded the first empire in western Europe; the Carolingian Renaissance centered on his court at Aix-la-Chapelle.
Charlemagne, perhaps born at Aachen in 742, later made the city his northern capital.
In later 8th century, Charlemagne conquered and made Austria into a border state of the Carolingian empire.
Frankish troops of Charlemagne took Barcelona in 801.