Excellency

From MiddleWiki

In our society "Your Excellency" is an honorific for those who have attained the rank of Baron/Baroness (both Landed Barons and Barons of the Court), Count/Countess, or Viscount/Viscountess*. You can also use terms of address such as "My Lord Baron" or "My Lady Countess."

An example of common usage "Lord Bob, may I introduce you to Her Excellency Baroness Sue?" or "Good evening, Your Excellency, are you enjoying the event?"

Historically, the Oxford English Dictionary reports its usage as a honorific for royal personages, ladies and others first used in the 16th century. (see www.oed.com for details.)

• In a rather moot point, as the Middle currently has no principalities, the Lord and Lady Heir of a Territorial Principality are addressed as "Excellency" as well.