"Your Majesty" is used when speaking directly TO the royal person. Servant speaks to King or Queen: "Excuse me, Your Majesty, may I bring you some tea?" "His Majesty" or "Her Majesty" is used when speaking ABOUT the royal person. Servant to kitchen staff: "The King would like his tea now. Will you take some to His Majesty?" or "The Queen would like her tea now. Will you take some to Her Majesty?" I am actually not sure which of these words should be capitalized (her majesty or Her Majesty), since this is not a usage I'm very familiar with. We have no majesty in the USA! :)