Frederick was a younger son of Count Louis of Montbéliard (died 1071) and Sophie, Countess of Bar.
He is documented in Italy from 1071 onwards as a witness to the charters of Beatrice of Bar and her daughter Matilda of Tuscany, to whom he was related via his mother.
[2] He ruled only nominally, as real power remained in the hands of Agnes' grandmother, Adelaide of Susa.
Frederick was presumably expected to succeed Adelaide, but he died before her in June 1091.
[3] With his wife, Agnes of Savoy, Frederick had several children, including: