Otto I, Holy Roman Emperor
In 843, after long disputes between the successors to Charlemagne, the Holy Roman Empire was broken into four parts. In 870, Metz and its province Lorraine allied with East Francia while remaining an autonomous duchy. In 962, when Otto I, Holy Roman Emperor, restored the Empire, Lorraine was designated as the autonomous Duchy of Lorraine, with Metz as its capital. It maintained this status until 1766, when it formally became part of France.