Union between Sweden and Norway
used as civil ensigns; the first official introduction of such a flag was in a regulation of 11 June 1748 describing the Danish civil ensign ("Koffardiflaget") for merchant ships. The Danish design was adopted for the flags of Norway (civil ensign 1821) and Sweden (1906), both derived from a common ensign used during the Union between Sweden and Norway 1818–1844, Iceland (1915) and Finland (1917).