 Oscar II became King on 18 September 1872, upon the death of his brother, Charles XV.At his accession, he adopted as his motto "Brödrafolkens väl" / "Broderfolkenes Vel" ("The Welfare of the Brother Peoples").While the King, his family and the Royal Court resided mostly in Sweden, Oscar II made the effort of learning to be fluent in Norwegian and from the very beginning realized the essential difficulties in the maintenance of the union between the two countries.