The universally educated landgrave composed music and wrote poems himself. He commissioned a large part of the interior painting of Wilhelmsburg Palace in Schmalkalden.
While he was successful in the field of arts, he made some unwise political decisions. The conversion of his landgraviate to Calvinism resulted in a war of succession which lasted for decades and in political isolation in the Thirty Years War.
In 1627 he had to resign and retire to Eschwege.