Some countries, for example Belgium and Great Britain, they are still monarchies and therefore obey court protocol. Here are some rules, to be followed.
The protocol specifies the dress for the presence of the monarch or members of the royal family – gentlemen in the evening should wear a tuxedo or tailcoat (according to the instructions in the invitation), and during the day – suit. Bright jacket (swallow) it is suitable for a garden party or a wedding. Ladies wear long dresses or afternoon dresses, appropriate to the circumstances. Hats and gloves are no longer compulsory.
If the monarch or a member of his family attends a ceremony or meeting, arrives last, and all the guests should be present by then. Guests rise to greet him and do not sit down, until he himself takes a seat. None of the guests leave before the monarch.
The invitation to the royal seat imposes completely different obligations. You should confirm its receipt at the secretariat of the royal palace, whose phone is always listed in the invitation.
When the monarch visits a private individual, it is fitting to await him on the threshold of the house and give him the place of host at the table. Depending on the circumstances, the lady of the house sits directly in front of him or on his left. If the king and queen go to an informal dinner together, they sit in front of each other, in the places of the master and the lady of the house. The hosts should present the court master of ceremonies with the guest list and table plan. The same protocol rules apply to rulers and cardinals.
When the monarch enters the living room, the guests get up. Custom wants, would you, to which the monarch is approaching, she bowed, but it is not obligatory. Addressing the ruler in the third person is welcome. When the Queen or Duchess shakes the man's hand, he bows and kisses her hand respectfully.
It is customary for the Belgian aristocracy to notify the court marshal of the wedding of their children, asking, to pass this information on to the royal couple.
(Association of the Nobility of the Kingdom of Belgium).