In 953, the German king Otto I had appointed his brother Bruno the Great Duke of Lotharingia.

In 959, Brunhad divided the duchy into Upper and Lower Lorraine; this division had becomne permanent following his death in 965.

The Upper Duchy is further "up" the river system, that is, it is inland and to the south.

Upper Lorraine is first denominated as the Duchy of the Moselle, both in charters and narrative sources, and its duke is the dux Mosellanorum.

The usage of Lotharingia Superioris and Lorraine in official documents begins later, around the fifteenth century.

The first duke and deputy of Bruno is Frederick I of Bar, son-in-law of Bruno's sister Hedwig of Saxony.Lower Lorraine disintegrats into several smaller territories and only the title of a "Duke of Lothier" remains, held by Brabant.

After the duchy of the Moselle comse into the possession of René of Anjou, the name "Duchy of Lorraine" is adopted again, only retrospectively called "Upper Lorraine".

At this time, several territories had already split off, such as the County of Luxembourg, the Electorate of Trier, the County of Bar and the "Three Bishoprics" of Verdun, Metz and Toul.