After her brother Giso V, Count of Gudensberg, the County of Hesse and the other vast possessions of the Gisones dynasty fell to her and her husband and thus fell to the Thuringian branch of the Ludowingians dynasty.
In 1122, Hedwig's mother, Kunigunde of Bilstein remarried to Henry Raspe I, who was Louis I's younger brother.
Via these two marriages, the Thuringian counts inherited an extensive triple heritage: In 1128 Hedwig gave birth to her son Louis II.
In 1148, Hedwig founded Ahnaberg Abbey, together with her second son Henry Raspe II, who at the time administered the parts of Hesse held by the Ludowingians.
A settlement grew between this abbey and the former Franconian royal court Chasalla (from Latin: Castellum, "castle"), on the left bank of the Fulda and this settlement developed into the city of Kassel, which became the capital of Hesse in the 13th century.