owned seems an odd term. colonized or joined to seems more appropriate
Norway was an independent kingdom until 1340, when the more-numerous Danes invaded them, and conquered them.
And then in 1814, because Denmark had sided with Napoleon, and Sweden with the allies, Norway was taken away from Denmark as punishment, and given to Sweden as a reward.
At times, a stray Norwegian or two who wanders into Free Republic will protest that no, they (the Norwegians) get along just fine with their neighbors the Swedes, as if everyone were brothers; that the Norwegians and Swedes party and carouse and have all sorts of good times together.....
.....which generally appears to contradict what outside observers note of the relationship, in which one discerns all sorts of subterranean--and some not so deeply buried--animosities and hostilities.
And so one is left with the impression that in reality, on the surface, the Norwegians and Swedes get along just dandy, but underneath, where it is more significant, there is much unarticulated anger and rage.
It is possible that Norwegian governmental officials are aware of this, and suspect that waving the old Swedish flag in front of usually-quiet and docile Norwegians, would arouse those ancient hatreds, much like waving a red cape in front of a bull.