Peignoirs originated in 19th century France. They were a rather utilitarian garment at that time. The Lady would often sleep in the nude for the convenience of The Master so a garment was needed for getting out of bed the next morning. And that was the peignoir.
So The Lady would get out of bed, have her morning pee in the chamber pot kept under the bed, go back to bed and ring for the maid to remove the pot. While the maid was doing that The Lady would choose and don one of her peignoirs. It was not fitting for the maid to see The Lady in the altogether. That was a pleasure strictly reserved for The Master.
The maid would come back and The Lady would take a seat while the maid brushed her hair. The peignoir was a garment for hair brushing time. The Lady of course wore her hair long to please The Master and long hair can get rather messed up in bed -- so brushing it out was the first order of the day. After that other preparations for facing the day would begin.
So the peignoir was a practical thing -- a dressing gown tied at the waist -- but The Lady would NEVER wear anything that was just practical. It had to look good too -- in case The Master came in during preparations. So the peignoir was usually in silk or satin and often in white. It had to be simple but flattering. So it could not be voluminous but should rather flatter the figure.
So that is how peignoirs originated. In more modern times their privacy use has largely disappeared and they come in sheer fabrics, cut in revealing ways and accompanied by matching panties: Not your old peignoir at all. I have however been old fashioned since I was aged six so I really enjoy seeing a lady with a nice figure in an old-fashioned peignoir.
But where do you buy one? There are many advertised for sale on the net but they all seem to be modern interpretations. Anne has a figure so I offered to buy an old-style one for her years ago -- but we just couldn't find one.
But lo and behold! Anne walked into my bedroom recently wearing a very nice peignoir in the original style. Anne's mother passed away a year or so ago and Anne inherited most of her clothes. Her sisters were to fat or too slim for them to fit. And among them Anne found exactly the type of peignoir I like. A bit sad that you need to have a 93 year old mother with good taste to acquire one but that is how the cookie crumbled.