MargreteI said:Well, I am 100% sure. They are descrendants of Georg I of Greece (Prince Vilhelm) who took over the less then stabile throne in Greece. Recognizing this King Christian IX (his father) made sure the title "Prince of Denmark" would follow his descrendants once Vilhelm took over the unstabile throne in Greece. Constantine is a descrendant of King Christian IX and therefore he is Prince of Denmark in his own right, though he does not have a claim to the throne.
They also carry danish diplomat passports without being danish citizens. That is unusual and requires some sort of rank.
Alas, you are 100% wrong. By the 1953 Act of Succession, Part II Section 9 of the Danish Constitution of 5 June 1953, the right of succession is limited to descendants of King Christian X and Queen Alexandrine. Also the Salic Law was eliminated allowing women to accede to the throne. All this was done because King Frederick IX had no male issue. The Danish Constitution also provides that members without rights to succession are NO MORE princes or princesses to (TIL) Denmark.
Thus, ALL Greek, Norwegian and British royalty lost their rights to the Danish throne. However, because they were left with the title, they are called out of courtesy alone, princes or princesses from/of AF Denmark.
So, former King Constantine of Greece for example retains the title of prince AF Denmark, while, say, Prince Joachim is prince TIL Denmark.
King Constantine's children's are neither TIL nor AF Denmark, they are NOTHING.