I found this story in E.S. Turner’s What the Butler Saw. Although Turner is deeply unspecific about which Duke (7th? 8th? 9th?) and which Duchesses (2nd and 1st, presumably) he’s referencing, I believe the first two are aristocrats from the early eighteenth century and the latter is from the late 17th century. That’s as close as I can make my estimation.
“Slowly, the dukes were cutting away some of their more parasitic retainers and scaling down the feudal style of living, but the more ostentatious of them continued to pattern their households on that of the Court.
“In his seat at Petworth, the Duke of Somerset treated his servants more royally than did the new Hanoverian kings. He allowed none to speak to him, communicating only by signs. When he set out in his carriage outriders scoured the roads to protect him from the gaze of common people.
“His dinner was announced ceremonially by an upper servant holding what resembled a bishops’ crozier: (forte) ‘MY LORD DUKE OF SOMERSET‘ (piano) ‘My Lord Duke of Somerset’ (pianissimo) ‘my lord duke of somerset – Your Grace’s dinner is on the table.’
“The Elderly Duchess of Buckingham, described by Horace Walpole as ‘more mad with pride than any mercer’s wife in Bedlam,’ exacted Court etiquette not only from her servants but from her friends; and on her deathbed she made her women promise that, though she lay senseless, they would not sit down until she was pronounced dead.”
“At Dalkeith, in Scotland, the greatest heiress in the three kingdoms, the Duchess of Monmouth and Buccleuch, also lived in near-royal state. She, too, kept everyone standing in her presence and when receiving guests she sat under a canopy. No letters were passed direct by inferiors to the Duchess; they had to go through the hands of the gentlewoman in waiting. It was an adequate scale of living, some may have thought, for one whose first husband, the Duke of Monmouth, had been executed for treason.” (16-17).
Of course, not every Duke was treated with the dignity accorded to his station. Horace Walpole’s Swiss footman “twice told the Duke of Würteemberg to call again, as his master was not yet out of bed. ‘Good God,’ said Walpole, ‘tell him to call again! Don’t you know he is a sovereign prince?’ The answer was: ‘No, I did think he was only a common Duke.’ (39-40).