Louis IV of Thuringia was a German nobleman who ruled as the Landgrave of Thuringia from 1217 until his death in 1227. He was a member of the House of Wettin and is known for his efforts to strengthen the power of his territory during a time of political fragmentation in the region. Louis IV was also a patron of the arts and supported the development of towns and trade. He is often remembered for his marriage to Elizabeth of Hungary, a union that brought together two influential families. Their relationship is celebrated in various legends, highlighting themes of love and devotion. Louis IV's legacy includes his contributions to the cultural and political landscape of medieval Germany.