How did one keep all those numerous titles straight when he addressed the members of the aristocracy and the titled?

Here are some of the MANY differences of which one needed to be aware:

“Lady” – used for the wife of a baronet or a knight (i.e., Sir Thomas Bertram’s wife in Mansfield Park is Lady Bertram)

“Lady” – used for a marchioness, countess, viscountess, or baroness (i.e., the wife of Viscount Lexford became Lady Lexford)

“Sir” – used for a baronet or a knight with his first name (i.e., Sir Thomas Bertram or Sir Walter Elliot from Persuasion)

“Baron” – used for a judge of the Exchequer Court or for a baron of the peerage upon formal occasions

“Lord” – used for an earl, marquis, or viscount – usually this was the title the man possessed (for example, the Earl of Linworth became Lord Linworth); barons were rarely spoken of as Baron Ashworth; instead, the man would be Lord Ashworth

“My Lord” – used for a peer below the rank of duke and to a bishop of the Church of England

“My Lord” – used for a lord mayor and judges of the King’s Bench and Common Pleas court

“Your Grace” – to a duke or duchess if the person making the address were below the gentry; the title is also used for an archbishop of the Church of England

“Duke” or “Duchess” – used for a duke or duchess and used by a member of the nobility or gentry

“Your Highness” – used for the nephews, nieces, and cousins of the ruling monarch/sovereign

“Your Royal Highness” – used for the monarch/sovereign’s spouse, children, and siblings

“Your Majesty” – used for the king or queen