sentences:  After struggling for recognition of his legitimacy, he died shortly after finally receiving it and was succeeded by his 13-year-old son Duke Christian IV, for whom his mother ruled as regent until he came of age.Christian IV was an enlightened and tolerant Duke whom the Duchy owed thanks for improvements in the field of religion.Mindful as he was of what would be expected if he was to succeed as Elector of the Palatinate and Duke of Bavaria, he converted to Catholicism.