Many people today do not realize that the so-called instrument that we know as the kazoo actually originated from a style of footwear in the Middle Ages. Fashion, seemingly, saw its rise and demise in a fairly short time period of only a decade or so, from about 1455-65, in a small geographical area around Aosta, Italy, on the border of France and Switzerland.
We have a single manuscript illustration depicting a mounted knight wearing kazshoes over the top of his sabatons (Fig. 1). We also have a vaguely written account of this type of footwear being worn into battle where it is said that it produced a loud buzzing sound, apparently meant to terrify enemy troops once the riders got up to speed.
Fig. 1: St. George and the Dragon by Friedrich Herlin, c. 1460, the only known illustration of kazshoes.
Specifically, the Chronicle (Morgan Library & Museum MS B.4, dated to 1450) tells us that “...siquidem rex sonitum audiri fecerat in castris inimicus, calceamenta tumultuantem susurrus, et equorum, et exercitus plurimi...” (for the king had caused the army of the enemies to hear the noise of loud-buzzing shoes and the noise of horses - the noise of a great army).
The basic structure of the shoe is simple: a squared-off heel, with an elongated, tapered toe, topped by an elaborate fastener disc. Some might consider it a derivative of the poulaine, and perhaps it was, but there are two significant differences.
First, the kazshoe is clearly symmetrical, whereas all known poulaines have definite left- and right-foot versions. Most likely this is to facilitate their quick application when arming before battle.
Second, while poulaines have long, stuffed toes, kazshoes apparently had a more rigid structure of thicker leather, sufficient for it to hold its own shape, and they are not stitched closed at the end. It is that open toe-tube that allows sufficient air flow through the shoe to produce its sound. Presumably they fit loosely, and the air vibrates the metal lames of the sabatons as it passes over them.
As for the large stiff disc on top, it seems to be overkill for simply keeping the shoe secured to the foot. This appears to be a stylistic choice but very well may have been functional, serving as a place to display the arms of the knight. Depending on the complexity of the design, it could have been painted, incised, or even embroidered (directly onto the leather, or with a cloth covering stitched to the disc).
Fig. 2: Close-up of the right kazshoe.
As the 15th century progressed, kazshoes seem to have fallen rapidly out of style, apparently with nothing to replace them amongst members of the chivalry. There seems to be little doubt that the ladies of court might have been the reason for this. The Libellus de modo confitendi of 1486 has one passage translated as “are there any who fervently desire to be required to listen ad nauseum to the screeches of this vile implement?” It apparently alludes to their displeasure with the noise, likening it to a swarm of angry waterfowl. It could also be the case that troops simply became accustomed to the noise and kazshoes were no longer effective.
Although I have not been able to determine how exactly medieval kazshoes morphed into today’s kazoos, as no intermediate objects have come to light, my guess is that drunken squires left with unwanted kazshoes learned they could blow through them to generate the same distinctive sound. It seems likely that at some point someone was able to reproduce them in wood, and later a thin metal such as tin, and finally today in plastic.