Christian, Prince Elect of Denmark
Christian was PrinceElect of Denmark since 1610 and Heir Apparent to the Throne of the Kingdom of Norway since 1603. Dying in 1647, he was succeeded by his younger brother, Prince Frederik.
Prince Christian was born at Copenhagen Castle to King Christian IV and Queen Anne Catherine of Denmark, Norway, etc. Christian was their second son and the oldest one living, as his elder brother Frederik had died in 1599, less than a year old. As such, his father saw him as the preferable heir to the Danish throne.
Source: Wikipedia