The history of the next forty years (1222–1261) is that of the strengthening of the Greek empire at Nicaea and the decadence and downfall of the other so-called empires, and especially of that of the Latin Crusaders in Constantinople. The successor of Theodore Lascaris was John Ducas Vataces, who during a reign of thirty-three years fortified his position at Nicaea and increased the prosperity of his empire. He restricted the boundaries of the Latin territory in Asia Minor to the peninsula formed by a line parallel to the Bosporus from Ismidt to the Black Sea. He rendered property and life safe, and in consequence the Greek population continued to flock into his territory. Even French soldiers in considerable numbers quietly slipped away from Constantinople to take service with Vataces. At the commencement of his reign he was attacked by the newly appointed emperor, Robert of Courtenay, and in the combat which ensued not only was Vataces successful, but the last of the knights who had taken part in the capture of the city were left dead on the field. Until Robert’s death in 1228, Nicaea had few troubles with the Latin empire. [Sidenote: Latin empire. John of Brienne, 1228–1237. Baldwin II., 1237–1261.] Robert’s successor was a boy of eleven, who continued nominally emperor under the title of Baldwin the Second for upwards of thirty years, but the Latin knights wisely placed power in the hands of John de Brienne. Indeed, the crusading leaders seem throughout the whole Latin occupation to have assumed a large measure of the imperial authority. The period is contemporary with that of the barons who resisted King John in England, and who continued to assert their independence under the reign of Henry the Third. The French barons in Constantinople had much of the same spirit, with the additional incentive to independence that, as the emperors were of recent creation, the glamour which had already gathered about the kingly office in England and France was absent. The emperor was indeed nothing more than _primus inter pares_, and his own designs were often set aside for those of his associates. No one can doubt that they acted wisely in appointing John de Brienne, but even he, with all his experience and caution, failed as his predecessor had done when he attacked Nicaea. [Sidenote: Baldwin visits France,] [Sidenote: and England.]