Louis IV was a 13th-century German nobleman who served as the Landgrave of Thuringia and Saxon Count palatine. Born in Creuzburg in 1200, he inherited his title in 1217 following the death of his father, Hermann I. A member of the Ludovingian dynasty, he was married to Elizabeth of Hungary and maintained close ties with Emperor Frederick II. Louis is remembered for his commitment to protecting the impoverished and for his participation in the Sixth Crusade, which ultimately led to his death in Italy.