In 718 she shook off the yoke of Byzantium by repelling the heresies of Leo the Isaurian; and when this insurrection menaced her with the domestic tyranny of the Lombard Kings, who possessed themselves of Ravenna in 728, she called the Franks to her aid against the now powerful realm.

Stephen II.

journeyed in 753 to Gaul, named Pippin Patrician of Rome, and invited him to the conquest of Italy.

In the war that followed, the Franks subdued the Lombards, and Charles the Great was invested with their kingdom and crowned Emperor in 800 by Leo III.
at Rome.
The famous compact between Charles the Great and the Pope was in effect a ratification of the existing state of things.

The new Emperor took for himself and converted into a Frankish Kingdom all the provinces that had been wrested from the Lombards.