▁to ▁order ▁the ▁use ▁of ▁the ▁ordinary ▁war ▁en sign ▁instead ▁of ▁the ▁blue ▁en sign ▁when ▁that ▁was ▁" app ropri ate ". ▁The ▁blue ▁flag ▁was ▁used ▁until ▁ 1 8 1 3 . ▁ ▁Union ▁between ▁Sweden ▁and ▁Norway ▁ ▁Union ▁flags ▁of ▁ 1 8 1 5 ▁and ▁ 1 8 1 8 ▁ ▁On ▁ 6 ▁June ▁ 1 8 1 5 , ▁a ▁common ▁military ▁en sign ▁was ▁introduced ▁for ▁the ▁two ▁un ited ▁kingdom s ▁of ▁Sweden ▁and ▁Norway . ▁This ▁flag ▁was ▁identical ▁to ▁the ▁former ▁triple - ta iled ▁military ▁en sign ▁of ▁Sweden , ▁with ▁a ▁white ▁salt ire ▁on ▁red ▁to ▁be ▁included ▁in ▁the ▁canton . ▁Pro posed ▁by ▁the ▁Norwegian ▁Prime ▁Minister ▁and ▁union ist ▁P eder ▁An ker , ▁the ▁white ▁salt ire ▁on ▁a ▁red ▁background ▁was ▁supposed ▁to ▁symbol ise ▁Norway , ▁as ▁the ▁country ▁had ▁previously ▁been ▁un ited ▁with ▁Den mark ▁and ▁initially ▁continued ▁to ▁use ▁the ▁same ▁flag ▁as ▁an ▁independent ▁country , ▁but ▁with ▁the ▁national ▁arms ▁in ▁the ▁canton . ▁ ▁Norwegian ▁ships ▁continued ▁to ▁use ▁the ▁Dan ish ▁civil ▁en sign ▁distinguished ▁with ▁the ▁national ▁arms ▁in ▁the ▁canton ▁north ▁of ▁Cape ▁Fin ister re , ▁but ▁had ▁to ▁fly ▁the ▁Swedish ▁civil ▁en sign ▁in ▁the ▁Mediter rane an ▁to ▁be ▁protected ▁from ▁pir ate ▁attacks . ▁A ▁common ▁civil ▁en sign ▁for ▁both ▁countries ▁was ▁introduced ▁in ▁ 1 8 1 8 , ▁on ▁the ▁pattern ▁of ▁the ▁naval