Conrad IV of Germany

Conrad (25 April 1228 – 21 May 1254), a member of the Hohenstaufen dynasty, was the only son of Emperor Frederick II from his second marriage with Queen Isabella II of Jerusalem. He inherited the title of King of Jerusalem (as Conrad II) upon the death of his mother in childbed. Appointed Duke of Swabia in 1235, his father had him elected King of Germany (King of the Romans) and crowned King of Italy (as Conrad IV) in 1237. After the emperor was deposed and died in 1250, he ruled as King of Sicily (Conrad I) until his death. Early years He was the second child, but only surviving son of Emperor Frederick II and Isabella II (Yolanda), the queen regnant of Jerusalem. Born in Andria, in the South Italian Kingdom of Sicily, his mother died shortly after giving birth to him and he succeeded her as monarch of the Crusader state of Jerusalem. By his father, Conrad was the grandson of the Hohenstaufen emperor Henry VI and great-grandson of Emperor Frederick Barbarossa. He lived in Southern Italy until 1235, when he first visited the Kingdom of Germany. During this period his kingdom of Jerusalem, ruled by his father as regent through proxies, was racked by civil war until Conrad declared his majority and his father's regency lost its validity. In 1235, Conrad was betrothed to a daughter of Duke Otto II of Bavaria. She died before the marriage could take place, but Conrad later married her sister. Rise to power When Emperor Frederick II deposed his eldest son, Conrad's rebellious half-brother King Henry (VII), Conrad succeeded him as duke of Swabia in 1235. However, the emperor was not able to have him elected king of the Romans until the 1237 Imperial Diet in Vienna. The electors were "the archbishops of Mentz [Mainz], of Treves [Trier], and of Cologne, the bishops of Bamberg, of Ratisbon [Regensburg], of Frisingen [Freising], and of Padua, the count palatine of the Rhine, the duke of Bavaria, the king of Bohemia, the landgrave of Thuringia, and the duke of Carinthia". This title, though not acknowledged by Pope Gregory IX, presumed his future as a Holy Roman emperor. Prince-Archbishop Siegfried III of Mainz, in his capacity as German archchancellor, acted as regent for the minor until 1242, when Frederick chose Landgrave Henry Raspe of Thuringia, and King Wenceslaus I of Bohemia to assume this function. Conrad intervened directly in German politics from around 1240. He led the short-lived anti-Mongol crusade of 1241.