In 1604 he inherited a part of
Hessen-Marburg after the death of
Louis IV of Hesse-Marburg who was childless. The other half went to
Maurice of Hesse-Kassel (or Hesse-Cassel), but since Maurice was a
Calvinist, Ludwig claimed a right on the whole of Hesse-Marburg. Lutheran professors of the
University of Marburg who refused to convert to Calvinism founded in 1607 the
University of Gießen which was named
Ludoviciana. This led to a conflict during the
Thirty Years' War, between Louis V, who stood on the side of the
Emperor, and Maurice, who was on the side of the Protestants. Hesse-Darmstadt suffered severely from the ravages from the Swedes during the conflict. The Landgrave died in 1626 and he was succeeded by
George II, Landgrave of Hesse-Darmstadt. In 1722,
Johann Georg Liebknecht, an astronomer at the University of Gießen, named a star, which he thought was a planet,
Sidus Ludoviciana after Ludwig V. ==Issue==