Ottokar was quickly forced back into Philip's camp by the imperial declaration of a new duke of Bohemia, Děpolt III. Subject to his recognition as duke, Ottokar had to allow his divorced wife to return to Bohemia. Having been completed this condition, he again ranged himself among Philip's partisans and still later was among the supporters of the young King
Frederick II. In 1212 Frederick granted the
Golden Bull of Sicily to Bohemia. This document recognised Ottokar and his heirs as Kings of Bohemia. The king was no longer subject to appointment by the emperor and was only required to attend
Diets close to the Bohemian border. Although a subject of the Holy Roman Empire, the Bohemian king was to be the leading electoral prince of the
Holy Roman Empire and to furnish all subsequent emperors with a bodyguard of 300 knights when they went to
Rome for their coronation. Ottokar's reign was also notable for the start of German immigration into Bohemia and the growth of towns in what had until that point been forest lands. In 1226, Ottokar went to war against Duke
Leopold VI of Austria after the latter wrecked a deal that would have seen Ottokar's daughter (
Saint Agnes of Bohemia) married to Frederick II's son Henry II of Sicily. Ottokar then planned for the same daughter to marry
Henry III of England, but this was vetoed by the emperor, who knew Henry to be an opponent of the
Hohenstaufen dynasty. The widowed emperor himself wanted to marry Agnes, but by then she did not want to play a role in an arranged marriage. With the help of the pope, she entered a convent. ==Family==