In the beginning of the 17th century, lots of goods from the new world was imported in Europe: spices, coffee, tobacco and silks. It became very fashionable to be depicted in a 'robe du chambre' or banian. It is from these garments the smoking jacket evolved. In the second half of the 19th century smoking became very popular in England, and a gentleman would retreit after dinner to the smoking room and the smoking jacket intended to absorb the smell of smoke and protect the gentleman's clothes from falling ashes. A smoking cap might have been worn with it. The smoking jacket kept its popularity well into the 20th century. Gary Grant, Fred Astaire and Dean Martin being enthusiastic wearers of this type of jacket. Sherlock Holmes must be the most famous of the smoking jacket fanatics. Probably the pipe has something to do with it.
All this makes me think of a time in history... I was young, the days were endless, we all would live forever and we smoked..