From the Roman period onward, there are records of honorifics used to address emperors, popes, and so on: "Your Grace," "Your Holiness," etc. Do we have any records of similar honorifics used in Bronze Age Egypt or Mesopotamia?
(Just to be clear, I'm not asking about royal titles like "Lord of X, Y, Z," but about honorifics used in direct address.)
If you are interested specifically in Bronze Age Egypt and Mesopotamia, you will likely enjoy Trevor Bryce's 2004 Letters of the Great Kings of the Ancient Near East; in short, yes, we do, although the evidence varies by civilization. Diplomatic/state correspondence accounts for one of the substantive source types.