Complex sentence: He supported Otto IV, who therefore confirmed the everlasting reign of the Wittelsbach family in Bavaria, but in 1211 Louis joined the Hohenstaufen party, Frederick II rewarded him with the Palatinate of the Rhine in 1214.
Split into simpler sentences: He supported Otto IV, who therefore confirmed the everlasting reign of the Wittelsbach family in Bavaria. But in 1211 Louis joined the Hohenstaufen party, Frederick II rewarded him with the Palatinate of the Rhine in 1214.