These Old Shades by Georgette Heyer

Mine host and hostess of the Black Bull at Le Dennier had never before entertained such quality at their humble inn. Madame sent a serving-man running hotfoot to her neighbour, Madame Tournoise, and presently that lady came hurrying in with her daughter to aid Madame in her preparations. When she heard that no less a personage than an English Duke, with his entourage, had arrived at the inn, she was round-eyed in wonderment, and when his Grace came slowly down the stairs clad in a coat of palest lavender, with lacing of silver, and a silver waistcoat, amethysts in his lace, and on his fingers, she stood staring open-mouthed.

His Grace went to the little parlour, and sent for writing materials. Mine host came bustling with the inkhorn, and desired to know whether Monseigneur would take any refreshment. His Grace bespoke a bottle of canary wine, and three glasses, and sat him down to write to his cousin. A faint smile hovered about his lips.