His success in the Rhineland was as great as it had been in Brazil, and he proved himself a most able and wise ruler.
The country was colonized with settlers from the lower Rhineland, land was brought under cultivation, forts were built, German laws and customs introduced, and gradually the woods and marshes were converted into lands of comparative fertility.
In 1609, John Sigismund had joined the Evangelical Union, probably to win support in the Rhineland, and the same consideration was doubtless one reason why, in 1613, he forsook the Lutheran doctrines of his family, and became an adherent of the reformed, or Calvinist, faith.
The victory of his French allies at Bouvines on the 27th of July 1214 greatly strengthened his position, and a large part of the Rhineland having fallen into his power, he was crowned German king at Aix la Chapelle on the 25th of July 1215.
Erzberger's power in German politics was based upon his great influence with the Catholic working classes in the Rhineland and Westphalia, in central Germany and in Silesia.