Another process was smoking, which almost certainly started by accident, and which later became formaldehyde tanning, as this substance is found in the vapors produced by burning green leaves and branches. It was soon discovered that the rotting process could also be stopped by drying, carried out by exposure to the sun or by the dehydrating action of salt. Vegetable tanning was also known in very ancient times although it is not clear how the tanning action of the tannin contained in the bark of some plants (especially oak) was discovered. Another method known since the earliest times is tanning, based on the use of alum, a mineral which is fairly widespread in nature, particularly in volcanic areas.
These methods, which gradually became more refined and efficient, allowed skins to be used in the ancient world and continued to do so for century after century up to the present day. That the use of these techniques was widespread is witnessed by numerous written documents and paintings as well as archaeological finds. In Mesopotamia between the fifth and the third millennium B.C., for example, the Sumerians used skins for long dresses and diadems for ladies. The Assyrians used leather for footwear but also for liquid containers and as inflated floats for rafts. The ancient Indian civilization first processed the type of leather known as the "Morocco" today.
The Egyptians also achieved considerable skill in processing leather, which they used for clothing (even for gloves), tools, arms or simply for ornament. The historian, Strabo, tells of an interesting use developed by Phoenicians who made water pipes from it. During Roman times, leather was widely used in all the provinces of the empire, and more efficient tanning techniques were introduced where they had not been developed locally.
​
The History of Leather
Leather tanning is without a doubt one of the oldest human activities. In the beginning, skins obtained from hunting and livestock breeding could be used for clothing or tents, but they became stiff at low temperatures, while they rotted with heat. It was probably then that attempts were made to render them more flexible and stronger by rubbing in animal fats, the first rudimental tanning process is mentioned in Assyrian texts and in Homers Iliad.