difficult as it would have been in Europe. In crusader Palestine, individuals and whole families tended to die much sooner and replacements, sang nouveau, were needed. 13th century Balian's descendants were among the most powerful nobles in the Kingdom of Jerusalem and the Kingdom of Cyprus. Balian's first son John of Ibelin, the Old Lord of Beirut, was the leader of the opposition to Emperor Frederick II when the latter tried to impose imperial authority over the crusader states. The family briefly regained control of the castle of Ibelin in 1241 in the aftermath of Frederick's Sixth Crusade, when certain territories were returned to the Christians by treaty. John had numerous children with Melisende of Arsuf, including Balian, lord of Beirut; Baldwin, seneschal of Cyprus; another John, lord of Arsuf and constable of Jerusalem; and Guy, constable of Cyprus. This Balian was married to Eschiva of Montbéliard and was the father of John II of Beirut, who married the daughter of Duke Guy I of Athens. John of Arsuf was the father of Balian of Arsuf, who married Plaisance of Antioch. Guy the constable was the father of Isabella, who married Hugh III of Cyprus. Balian of Ibelin's second son Philip was regent of Cyprus while his niece, the widowed Queen Alice, needed help to govern. With Alice of Montbéliard, Philip was the father of John of Ibelin, count of Jaffa and Ascalon, regent of Jerusalem, and author of the Assizes of the High Court of Jerusalem, the most important legal document from the crusader kingdom. John married Maria, sister of Hethum I of Armenia, and was the father of James, count of Jaffa and Ascalon and also a noted jurist; and of Guy, count of Jaffa and Ascalon and husband of his cousin Maria, Hethum's daughter. Several members of the family went to the new kingdom of Cyprus at the beginning of the 13th century. Most of the rest moved there as the mainland kingdom was lost piece by piece. No members of the Ibelin family seem to have gone to any other country during this period. At this time, some of the Embriaco lords of Gibelet, relatives of the Ibelins, also took the name of "Ibelin" because of their common maternal descent. Despite the family's modest origins on the paternal side, the Ibelins during the 13th–15th centuries were among the highest nobility in the Kingdom of Cyprus, producing