When referring to a specific person (i.e- His Highness Prince Philip, or Her Highness Queen Elizabeth) the first letter of the word ("H") is capitallized.
P
Her Royal Highness or His Royal Highness.
Highness is a lower rank of a Royal Highnessbecause a Highness may be a distant relative of the monarch whereas the a Royal Highness may be a sister, brother, son, daughter etc.
The duration of Your Highness is 1.7 hours.
That is the correct spelling of the royal title "Your Highness."
Your Highness was released on 04/08/2011.
The Production Budget for Your Highness was $50,000,000.
Your Highness was created on 2011-04-08.
The plural of (royal) highness is (royal) highnesses.
Your Royal Highness or Imperial Highness It depends on the country and rank of the Princess because some princesses have the style "Highness" insetad of Royal or Imperial Highness.
No, either Her/Your Royal Highness.
The duration of Sigh of His Highness is 2700.0 seconds.