That is such a cool thing! I suppose that nameing system doesn't apply to Queens?
Ahh...heres more of the royal Danish history
Actually it does. The current ruling queen is called Margrethe II. The II is kinda misleading because in reality it should be Margrethe I since she is the only one that has been the official ruler, after a change in the constitution in 1953.
Theres been 2 other Margrethe before. They first Margrethe (1259-1264) ruled on behalf of her son Erik VI Klipping, since he was to young to take over the crown after his father Christoffer I. She has not been recorded in history as being the ruler.
Then theres Margrethe I, the official 1st Queen ruler. The history of this is a bit complicated but in short she ruled the "Kalmar union" from 1375-1412 (Norway, Sweden and Denmark) on behalf of Erik VII.