One of the most important methods of producing leather, either as such or on furs, was with the aid of certain vegetable extracts, known as the tannins, from which the process of tanning gets its name. The discovery of the value of these materials for converting the decaying raw skin into a leather which could be preserved for an almost indefinite length of time, and which was flexible and soft as desired, was of far-reaching importance. For it is only in very recent times that these tannins have been superseded in part by new tanning substances whose use is simpler and more time-saving. Yet there are unmistakable indications that the tannins were employed for tanning at a period which reaches back to the dawn of history. Although it is scarcely probable that the people who used these materials could have known of the existence or the nature of the particular substances in the vegetable extracts which actually effect the tanning action, experience taught them to employ these plants which possessed the highest content of active ingredients, and which, consequently, were most effective in use. Tychios, of Boetius, a Greek supposed to have lived about 900 B.C. and mentioned in the _Iliad_, is considered the oldest known tanner, and was regarded by Pliny, a Roman writer, as the discoverer of tanning, and of the use of the various vegetable tanning materials. At any rate, the Greeks used the leaves of a so-called tanning-tree, which was probably the sumach. The Egyptians worked with the acacia, while the Romans used as tanning materials the barks of the pine, alder and pomegranate trees, also nut-galls, sumach and acorns. The Romans were quick to employ methods used by the peoples whom they conquered, and it is in this way that they learned the use of many of the plants mentioned, for tanning purposes. Many other ancient peoples had various processes of tanning, the methods probably differing in each country. Thus the Chinese, Syrians, and much later, the Moors, were each known for proficiency in a certain class of leather tanning. It has been said that in general, even up to modern times, tanning with nut-galls was the characteristic method of the Orient; with oak-tan, that of the Occident, while the use of alum is regarded as the method peculiar to the Saracens.