King of Jerusalem (1210-1212) as consort to Maria of Montferrat (“la Marquise”), queen of Jerusalem, and subsequently regent (1212-1225) for their daughter, Isabella II. John ended his career as Latin emperor of Constantinople (1231-1237).
John was the fourth son of Erard II, count of Brienne in Champagne. In 1208, he was chosen either by Philip II of France or by the High Court of the kingdom of Jerusalem to marry the heiress to that realm, Maria (“la Marquise”) of Montferrat. He has often been regarded as a poor choice, as he was without the resources to support the kingdom, and some considered him too old for the task, though on his marriage he was probably only in his thirties. He had military prowess, a family with a crusading pedigree, and the support of Philip II of France, Pope Innocent III, and his fellow Champenois lords, together with a kinsman already prominent in the East (Walter of Montbéliard) to recommend him.
On 13 September 1210, John reached Acre with 300 knights. He married Maria on the following day, and they were crowned in Tyre on 3 October 1210. John soon led his force on a raid into the hinterland but achieved little; in May 1211 he secured a six-year truce with the Muslims. In 1211 or 1212, a daughter, Isabella (II), was born to the couple, and Maria died. John was no longer king, but regent for his daughter. However, he continued to style himself “king” and was recognized as such by the church, although he may have encountered opposition from the Frankish barons.
In 1214 John formed an alliance with the kingdom of Cilicia through marriage to Stephanie, the eldest daughter of King Leon I. John took a prominent part in the Egyptian campaign of the Fifth Crusade (1217-1221), but he clashed with Pelagius, the papal legate, over its direction. When Leon died in 1219, John withdrew from the crusade army to pursue a claim to the Cilician throne, but he rejoined the crusaders when both Stephanie and their son died.
In March 1223 John attended a conference held at Fer- entino in Italy with Pope Honorius III, the Holy Roman Emperor Frederick II, and other representatives from Outremer. It was agreed that Frederick would marry John’s daughter Isabella. John then toured Europe seeking assistance for the Franks in Outremer and, in 1224, married Berengaria, sister of Ferdinand III of Castile. In November 1225, Isabella was married to Frederick II, who then demanded that John surrender the kingdom of Jerusalem to him, to which he was forced to accede. In 1228-1229 Frederick, who was also king of Sicily, had to curtail an expedition to the Holy Land when John led a papal army against his territories.
In 1228 Robert, the Latin emperor of Constantinople, died, leaving an eleven-year-old heir, Baldwin II. The regency council needed a military leader to defend the empire at a crucial juncture and, in April 1229, it was agreed that John’s daughter by Berengaria, Mary, should marry the young emperor, while John would become co-emperor for life. In 1231, John was crowned in Constantinople. The empire was impoverished and suffered constant attack and, despite some minor victories, was still in danger at the time of John’s death. In 1237 he took holy orders with the Franciscans, whom he had patronized, and he died on 23 March.