Conrad II was the sole male child of Frederick II, the Holy Roman Emperor and Yolande, queen-regnant of Jerusalem. He was born in 1228CE; his mother died in the child-birth and he accordingly succeeded to the throne, his father acting as regent. Frederick also sought to claim the throne in his own right, and appointed Balian d'Ibelin as his regent, whilst he returned to Europe, from where he dispatched one of his imperial Marshals, as "guardian of the kingdom" (to balance out the Ibelin power-base). However when Conrad's elder step-brother, Henry, revolted, Frederick deposed him from the Imperial succession, and had Conrad elected as King of the Romans in 1237.
In 1243, as Conrad had reached his majority, he was invited back to Jerusalem, to rule in his own right, and Alix/Alice of Champagne (by virtue of being the closest relative of Yolande) was elected regent, along with her husband, Ralph, Count of Soissons. In 1244 Alix died and Henry of Lusignan, King of Cyprus, who descended from Guy of Lusignan, a consort of a former queen, Sybilla, claimed the regency.
In 1245 the pope took issue against Frederick, and Conrad was deposed. A counter-king of Germany was elected, who defeated Conrad in battle but then died. At the same time, Conrad's title in Jerusalem was challenged (it is not clear that he ever actually visited the Holy Land) and from then on the kings of Cyprus claimed the rightful rule of what was left of the former Crusader kingdom.
Conrad married, in 1246, the daughter of the Duke of Bavaria. He succeeded his father as Emperor in 1250 (as well as picking up the throne of Sicily) and in 1252, a son, Conradin, was born, who succeded him nominally on the thrones of Jerusalem and Sicily.
Meanwhile Louis of France had come to Palestine on Crusade, and had tried to instil some unity among the baronage, but departed without either achieving this, or having any real impact on the disputed succession. Henry died (in 1257), and his successors claimed the throne for his son, Hugh; others insisted that Conradin should hold the throne.