thumb|upright|Prince Carl's maternal great-uncle, Oscar II of Sweden, who was King of Norway until October 1905. Following several years of disagreements on various topics, the Union between Sweden and Norway which had existed since 1814 was dissolved in 1905. The union was unilaterally dissolved by the Storting (Norwegian parliament) on 7 June, and the dissolution was later confirmed by the Norwegian people in the 1905 Norwegian union dissolution referendum held on 13 August. After weeks of negotiations, the dissolution of the union was then recognized by Sweden on 23 September in the Treaty of Karlstad, mediated by the great powers of Europe. Its provisions included the full recognition of Norway's sovereignty and the abdication of the Swedish King Oscar II from the Norwegian throne. One month later, the union was formally dissolved as King Oscar II on 26 October signed the documents recognizing Norway as an independent state, and abdicated as Norwegian king on the same day.
thumb|upright|Prince Carl's maternal great-uncle, Oscar II of Sweden, who was King of Norway until October 1905. Following several years of disagreements on various topics, the Union between Sweden and Norway which had existed since 1814 was dissolved in 1905. The union was unilaterally dissolved by the Storting (Norwegian parliament) on 7 June, and the dissolution was later confirmed by the Norwegian people in the 1905 Norwegian union dissolution referendum held on 13 August. After weeks of negotiations, the dissolution of the union was then recognized by Sweden on 23 September in the Treaty of Karlstad, mediated by the great powers of Europe. Its provisions included the full recognition of Norway's sovereignty and the abdication of the Swedish King Oscar II from the Norwegian throne. One month later, the union was formally dissolved as King Oscar II on 26 October signed the documents recognizing Norway as an independent state, and abdicated as Norwegian king on the same day