 It is likely that in these years, when the Lombard kingdom was ruled by sovereigns of Friulian origin and the central power was particularly strong, that the autonomy of the duchy was very limited.An indirect piece of evidence for this is the fact that Istria, which was conquered by Aistulf after he became king, was not annexed to the Duchy, but remained under direct royal control.After the Siege of Pavia in 774, the Lombard kingdom was conquered by Charlemagne who was proclaimed "By Grace of God, King of the Franks and Lombards."