The Vikings already produced decorative chains from wire by knitting it around a wooden pole. This technique is also known from the Romans (knitted chains were found in ancient roman graves). Today, this kind of chain is still known as knitted chain. However, there is another technique which is known for several thousand years. Hand-made chains were already done 3000 B.C. and can be attributed to the ancient Egyptians, Sumerians and Etruscans.
I manufacture such chains from various precious metals. The pictures above show some of these so-called "loop-in-loop" chains made from fine silver (some of them have been oxidised). I also use gold wire for such chains. Note that all necessary metal connections are fused - no solder is used in producing these chains.
I usually use a clasp which is also known since ancient times. This "S"-shaped hook is done by hand as well and is forged. This forging process leads to a springy behaviour and makes sure that the chain ends do not become unhooked from the clasp unintentionally. Of course, all other kinds of clasps can be used with the chains as well.