The Danish Royal House may be traced back to Gorm the Old and his son Harald I Bluetooth. The latter can be dated and located with certainty as he united Denmark. The two great lines of the Danish Royal House are the House of Oldenborg and the House of Glücksborg. The first representative of the House of Oldenborg became King in 1448, and the last King of the House of Oldenborg was King Frederik VII, as he had no heir to the throne. In 1863, the first representative of the House of Glücksborg became King, and the present Royal Family are direct descendants of this Royal House.