Career
He had the title Count of Schleswig-Holstein. In 1643, he was sent to Russia to marry Irene of Russia, the daughter of Tsar Michael of Russia, but as he refused to convert to the Orthodox faith, he was kept prisoner until 1645. In 1648, he came in to conflict with his half-brother Frederik III of Denmark because of his wish to be elected king instead of Frederick, and after this, he lived abroad.
He served in the Swedish army from 1655 and was killed in Poland in 1656.