Frederick II, Duke of Upper Lorraine

Frederick II (c. 995–1026), son of Thierry I of the House of Ardennes and Richilde von Blieskastel, daughter of Folmar III, Count in Bliesgau, was the Count of Bar and Duke of Lorraine, co-reigning with his father from 1019.

On the Emperor Henry II's death in 1024, he joined Ernest II, Duke of Swabia, in revolt against the new king, Conrad II. Soon they made peace and recognised the new king. Frederick died in 1026.

Frederick married Matilda of Swabia, daughter of Herman II, Duke of Swabia, and sister-in-law of Conrad. Frederick and Matilda had:

Sophia, Countess of Bar and Pont-à-Mousson, married Louis, count of Montbéliard Frederick Beatrice, married firstly Boniface, Margrave of Tuscany, and secondly Godfrey III, Duke of Lower Lotharingia; mother of Matilda of Canossa