Hi everyone - I am a medieval historian and I writing a conference paper about a recipe in a 13th-century work known as The Book of Charlatans. The recipe says it is for making weapons better. Here is the translation: "Take equal parts of oleander and basil and pound them till they reach the consistency of a liquid. To this add colocynth oil and then boil the lot till it's reduced to one quarter." After this you heat a weapon and then quench it slowly in this liquid.
So my question for anyone here is what do you think these ingredients - oleander, basil and colocynth oil - are actually doing? How could this recipe change the sword?