Wax hardened leather works reasonably well for SCA combat and can be made with medieval technology. I believe, however, that it is unlikely that it is the form of hardened leather used for armor in the Middle Ages. The reason is that it is too easy to cut. Beeswax is a lubricant, and a stiff material, like waxed leather or half frozen meat, is easier to cut than a limp material. So although wax hardened leather protects well against the blunt weapons we use, it would be very poor protection against a sword or arrow. The purpose of this essay is to describe my best guess at medieval cuirboulli. The technique is easier and less expensive than the one I described in my previous article, and the resulting armor provides reasonable protection against real weapons as well as rattan. Start with vegetable tanned leather of at least eight ounces in thickness (1/8"--an ounce corresponds to 1/64" of thickness). Soak it briefly in water. The purpose of this soaking is to make the effect of later immersion in hot water more uniform. Heat a pot of water to about 180 degrees. Immerse the wet leather in it for about a minute, watching for it to darken, go limp, and begin to curl up. When it does, remove it. The leather will now be very stretchy. To make an elbow kop, stretch your piece of leather (cut, in advance, to the appropriate shape) between two nested bowls, of about 8" diameter. Let the leather cool and dry. If you are making flat pieces, such as scales or lamellae, take the piece of leather out of the water and put it between your kitchen counter and a cutting board, or some equivalent pair of flat surfaces, so that it will harden flat. Then cut it to shape with a saw. The process has three effects on the leather. It makes it harder. It shrinks and thickens it. It makes it darker. These effects are irreversible. The longer you leave the leather in the water the more all of these things occur. If you leave it too long, it will be very hard--and somewhat brittle. One minute at 180 degrees seems to provide about the optimal tradeoff between hardness and brittleness--but experiment for yourself. You should get shrinking to about 7/8 in each direction, and thickening by about 25%. The process can be done in boiling water, although I find the result less uniform and less satisfactory. About a twenty second immersion produces the effects described above. About 40 seconds gives you shrinkage to 2/3, roughly doubles thickness, and gives a very hard, dark leather. Leather is not a uniform material; its characteristics vary with where on the hide it is from. Part of learning to use this technique is experimenting with scrap pieces, so that you can tell by the appearance of the leather when it has been in the water long enough for your purposes. In addition to all its other advantages, this process is also etymologically correct. "Cuirbouilli" means "boiled leather."