What is Leather?
Leather is made from the skins of animals. You can make leather out of the skin of any animal, but cows have the thickest skins to make the strongest leather. After the shepherd or the butcher killed the animal, he skinned the animal. Then a tanner (someone who makes leather) made the skin into leather. In some cultures it was mostly men who made leather. In other cultures it was mostly women. There were a lot of different ways of making leather. First you scraped all the flesh off the leather with a bone or stone scraper (later on, people might use metal knives).
Then they would need to process the skin with some kind of chemical. Sometimes they used salt.A lot of people used urine (you know, pee!). Tanners (people who made leather) would go around and collect urine from public toilets and from peoples' houses and take it back to their store in jars. They would let the urine stand around in the jars for a week or so until it turned into ammonia, and then they would pour the ammonia on the leather to cure it (to make it into leather). This made tanners and tanners' shops smell terrible, and mostly they were outside of town, right on the edges of towns, where people wouldn't have to smell them so much.
Many things in the ancient and medieval worlds were made out of leather. People made belts and shoes out of leather as we do today. They also made leather jackets and protective aprons and hats and sometimes pants out of leather. They used leather straps to carry boxes and bags. But people also used leather for lots of things that we don't use it for today. This was mainly because they didn't have plastic, and metal was very expensive, and glass and pottery were too breakable. People used leather bags to carry water and wine. They used leather strings to tie up their hair. Sometimes people used sheets of leather to cover doors or windows, or even as paper to write on.
Before people began to spin wool and flax into cloth, they made more of their clothes out of leather and furs. Once they began to have wool and linen cloth, they didn't need leather as much for clothes, but it was still used for many many things.
From Cow to Shoe, by Ali Mitgutsch (1981). For kids, translated from German.
Leatherwork, by Sylvia Grainger (1976). Lots of projects to do with leather.
Studies in Ancient Technology: Leather in Antiquity - Sugar and Its Substitutes in Antiquity - Glass, by R. J. Forbes (2nd revised edition 1997). Only part of the book is about leather, but it will tell you everything you need to know about leather in ancient Greece and Rome. By a specialist, for adults.