From the 15th century, at least up to 1660, the heir apparent of the King of Denmark and Norway was generally titled "Prince of Norway", in recognition to his hereditary right to succeed to the Norwegian throne upon the death of the king, as opposed to the need to pass an election in order to succeed to the Danish throne. Other members of House of Oldenburg, including any younger siblings of the Prince of Norway, were not called princes or princesses of Norway, but the title "Heir of Norway" was sooner or later accorded to them.