A mixture of tin and any one of several possible other metals, Pewter has been around for thousands of years; with the earliest examples of its use being found as far back as the 15th Century BC, in Egypt. This is not really all that surprising, as that would have been in the middle of an era known as the Bronze age; a time which is literally defined by the use of metals like copper and tin, and their alloys.
Materials that were common in the Bronze Age were not popular due to their properties exactly; but more because at the time it was difficult to mine and extract other metals, like iron, from their natural ores. Metals like copper and tin on the other hand were easy to separate because they have relatively low melting points compared to other metals. Pewter shares this low melting point, as irrelevant of what other metal it is made up of, it will never have a melting point higher than 230°C.
This has never really hindered it though, in fact it is partially because of this that it has been so successful. By being able to melt it easily, it was possible for people to experiment with different combinations and percentages of the metals used to create pewter; as a melted metal is able to absorb higher levels of other elements, than if it is just heated to the point of being soft.
Being versatile in this way, as well as physically malleable, led to pewter being used to create all sorts of objects, most commonly household items like plates, dishes, cutlery, mugs and cups; but it was also used to create decorative pieces like vases, which led to it being used prominently by the church until wide-spread glass production became possible during the 18th Century.
As mentioned previously, pewter is made primarily of tin, with the amount of tin rarely dipping below 85%; but as that would suggest, it also contains traces of other metals. There are a number of metals that have or still are used to create pewter, with copper, antimony, bismuth, lead and silver being the most usual.
Naturally some of these metals are not used often to make pewter these days; lead for example is rarely, if ever, used due to the harmful effects it can have on the human body. That said, there is still no serialised way to make pewter, as it is often done differently depending on where it is being made. For example the pewter made in Europe, by in large, contains less tin that the pewter made in Asia; making Asian pewter softer than its European counterpart.