Making a fictional world has me wondering what the minimum tech requirement would be to produce wire.
Wire rope was produced in the 1830s, but wire has been made for thousands of years.
The simplest way to make wire is by forging, to just hammer your piece of metal into a wire shape. This works well with very malleable metals like gold, but it's difficult to make the wire uniform. Basically, this method works well for short pieces of gold wire, but isn't so good for long pieces of wire.
Another technique is to beat the metal into a thin sheet, and then cut that sheet into strips. The strips can then be hammered into a round shape. The strips can be twisted before that hammering-to-round. This is a very old technique, and is mentioned in the Bible; in Exodus 39:3,
And they did beat the gold into thin plates, and cut it into wires
Again, this method is well-suited to very malleable metals such as gold.
The third major method of wire-making is drawing, where the metal is pulled through a hole slightly smaller than its width. As the metal is pulled through, it is forced to become smaller:
It can be drawn through a series of successively smaller holes, becoming smaller each time, until the desired size is reached. The piece of material with the hole is called a draw plate; the hole is a die, and a draw plate can have multiple dies. Different materials can be used, but the die needs to be harder than the metal being made into wire. It is much easier to produce uniform wire by drawing than by either of the first two techniques. Wire-drawing was already being used in ancient Egypt, to produce gold wire. The Egyptian method started with the second technique above, starting with a sheet, cutting it into strips, and twisting them. These twisted ribbons where then drawn through the die.
We don't know when drawing started being used for iron wire. The oldest European draw plate used for iron wire I know of is a 9th century Viking find. (One famous use of wire by the Vikings was for making mail armour.) The process is illustrated in Medieval art:
Thicker wire can be drawn more readily using a winch:
and even thicker wire using water-power:
(The last two illustrations are from http://combatarchaeology.org/artefact-of-the-month-the-mail-chausses-of-molledalen-buskerud/ which discusses the making of mail armour.)
The big advance which led to wire rope was increasing mechanisation. First, the increasing use of machinery made the wire-drawing process faster and cheaper, and mechanised roll-forging made it faster and cheaper to produce the round pieces of iron to start the drawing process.
Video of Medieval-style hand-drawing: https://www.britannica.com/video/180089/visit-museum-Germany-Altena
Modern mechanised drawing through a series of dies: https://www.youtube.com/watch?v=wlWkz9hjASo
In summary, Medieval technology is easily enough for hand-drawn iron wire.
Further reading:
Brian D. Newbury and Michael R. Notis, "The History and Evolution of Wiredrawing Techniques", JOM 56(2), 33-37 (2004)
