the supremacy of the Archbishop of Mainz. Henry was bestowed with Eschwege and the Boyneburg (with Sontra), strengthening his position in Hesse. By skillful diplomacy he gained the cities of Sooden-Allendorf, Kaufungen, Witzenhausen, Immenhausen, Grebenstein, Wanfried, Staufenberg, Trendelburg and Reinhardswald. In 1263 Henry had married Adelheid of Brunswick, daughter of Duke Otto of Brunswick, who bore him four daughters and the sons Henry ("the Younger") and Otto. After Adelheid's death in 1274, Henry had married Mechthild, daughter of Dietrich VI, Count of Cleves, who bore him another four daughters and the sons John and Louis. Uncertainty over succession In 1292 internal conflict arose about the question of Henry's successor. Mechthild of Cleves demanded on her sons receiving a share of the heritage, while Henry and Otto, Henry's sons by his first wife, insisted on excluding their half-brothers from the inheritance. This led to civil war lasting throughout the rest of Henry's lifetime. Henry died in Marburg during the conflict, and was buried there in St. Elisabeth's Church, which became the gravesite of the succeeding Landgraves for several more centuries. After his death, the inheritance was divided between Otto, who received Upper Hesse (Oberhessen) around Marburg, and John, who received Lower Hesse (Niederhessen), centred on Kassel. John's younger brother Ludwig had entered the clergy and became bishop of Münster in 1310. Children First marriage (1263) to Adelheid, daughter of Otto I, Duke of Brunswick-Lüneburg (1244–1274) Sophia (1264–after 12 August 1331), married 1276 to Otto I, Count of Waldeck. Henry the Younger (1265–23 August 1298), married in 1290 to Agnes of Bavaria, Margravine of Brandenburg-Stendal. Matilda (1267–after 1332), married to: 1283 Count Gottfried of Ziegenhain; after 11 October 1309 Philipp III of Falkenstein-Münzenberg. Adelheid (1268–7 December 1315), married 1284 to Count Bertold VII of Henneberg-Schleusingen. Elisabeth (1269/70–19 February 1293), married c. 1287 to Count Johann of Sayn (bg). an unnamed son (c. 1270–c. 1274). Otto (c. 1272–17 January 1328). Second marriage (1276) to Mechthild of Cleves, John (died 1311, Kassel). Elisabeth (c. 1276–after 6 July 1306), married to 1290 Duke William of Brunswick-Wolfenbüttel; 1294 Gerhard of Eppstein. Agnes (c. 1277–1335), married to Burgrave John I of Nuremberg. Louis (1282/83–18 August 1357), Bishop of Münster in 1310–57. Elisabeth (died after 30 October 1308), married in 1299 to Count Albert II of Gorizia. Katharina (died 1322), married to Count Otto IV of Orlamünde. Jutta (died 13 October 1317), married 1311 to Duke Otto of