 His works, which included his speeches, translations of Herder's "Cid" and Goethe's "Torquato Tasso", and a play, "Castle Cronberg", were collected in two volumes in 1875–76, and a larger edition, in three volumes, appeared in 1885–88.In 1859, Prince Oscar became heir-presumptive to the thrones of Sweden and Norway, as his eldest brother King Charles XV of Sweden/Charles IV of Norway was without a legitimate heir, having lost his only son, Prince Carl Oscar, Duke of Södermanland, to pneumonia in 1854.His second elder brother, Prince Gustaf, Duke of Uppland, had before died of typhoid fever in 1852.