Louis IV, Landgrave of Thuringia
Louis IV the Saint , a member of the Ludovingian dynasty, was Landgrave of Thuringia and Saxon Count palatine from 1217 until his death. He was the husband of Saint Elizabeth of Hungary.
Louis was born at Creuzburg Castle, the second son of Landgrave Hermann I of Thuringia, from his marriage with Sophia, a daughter of the Wittelsbach duke Otto I of Bavaria. During the German throne quarrel between the Hohenstaufen ruler Philip of Swabia and his Welf rival Otto IV, his father switched sides several times and tried to expand his own influence by betrothing his eldest son Hermann to the Hungarian princess Elizabeth, daughter of King Andrew II. The young girl arrived in Thuringia in 1211 to be raised at the Ludovingian court, then a venue for poets and minnesingers like Walther von der Vogelweide or Wolfram von Eschenbach.
Source: Wikipedia