For 10 points name this cultured but eccentric thirteenth-century monarch whose contemporaries referred to him as Stupor Mundi or the wonder of the world.
In return for securing the election of his son Henry as his successor, this Holy Roman Emperor confirmed and enhanced the autonomy of the German princes of the Holy Roman Empire through his Confederation with the Ecclesiastical Princes. In contrast, in his capacity as King of Sicily, this ruler established a strong centralized government thorough his Constitutions of Melfi and converted his court at Palermo into a major cultural center that attracted Greek and Muslim scholars. This husband of Yolande of Jerusalem bought Jerusalem from the Ayyubids before going on the Fifth and Sixth Crusades. However, he was also excommunicated four times during his lifetime and was the only medieval emperor consigned to hell in Dante's Divine Comedy. For 10 points name this cultured but eccentric thirteenth-century monarch whose contemporaries referred to him as Stupor Mundi or the wonder of the world.
In return for securing the election of his son Henry as his successor, this Holy Roman Emperor confirmed and enhanced the autonomy of the German princes of the Holy Roman Empire through his Confederation with the Ecclesiastical Princes.
{Frederick II} of Hohenstaufen [prompt on {Frederick}; accept {Stupor Mundi} until mention]