Louis I, Landgrave of Thuringia, thanks to his marriage to Hedwig of Gudensberg, obtains the rule over an extensive heritage, after the death of his father-in-law, Count Giso IV, which leads to the union of Thuringia and Hesse.
In 1137, Louis had become Landgrave of Hesse-Gudensberg as well.
His close relationship to the King Lothair III had favored his rise into the rank of a prince.
After the death of Lothair, in 1137, Louis had decided to support the Hohenstaufen in their struggle for power in the Reich against the Welf party.
The Landgrave dies on January 12, 1140 and is buried inside the abbey of Reinhardsbrunn.
Louis has a daughter, Judith of Thuringia, who will become the second wife of king Vladislaus II of Bohemia.
