Seeing this particular clothing item at YKW reminded me that I had once been told that the reason men’s suits had buttons at the cuffs was because Napoleon didn’t want his soldiers wiping their noses on their sleeves. Military chic being what it is, I guess the strategically-placed buttons quickly leapt over to civilian fashion.
So… this knitted item is from the Emily Post collection?
Edit: Duly corrected by Mara, I checked up on that second-hand assertion. The all-knowing Internet provides an assertion of Frederick the Great of Prussia, which probably preceded Napoleon by a couple of decades; turning to print matter from a time when people did more research, Wilcox’s The Mode in Costume illustrates buttons on the cuffs of a French man’s coat in the early 18th century (but those buttons are arranged around the periphery of a turn-back cuff, not along the forearm). The illustrations showing clothing from the Louis XVI (right before the Revolution) do show buttons aligned with the length of the forearm starting at the cuff, and this matches the timing of Frederick of Prussia. A quick skim of the text didn’t turn up any specific mention about the placement of those buttons. But yes, indeed, before Napoleon.