Actually oldest European monarchy...Japan is oldest world.
I think they mean in an unbroken line of succession. Queen Margrethe's direct-line ancestors have been royal rulers in Denmark since 1101 AD as a matter of historical record.
The Japanese Emperors' line is supposedly unbroken from 600 BC, but historical records do not go back much farther than 1300.
——Actually oldest European monarchy...Japan is oldest world. ——
Last time I checked Japan was not in Europe....western civilization....
But your point is taken...