One of the things I’ve found really interesting about researching the history of knitting has been the way ideas travel from one place to another. As a textile art, knitting evolved rather recently (12th-13th century) as opposed to weaving that appears to be about 8,000 years ago in Peru. Felt is likely older, nålbinding is about 6500 years old, and flax cultivation about 8,000 years old (although that was probably as a food/oil source rather than for textiles).
Part of what made knitting possible was the development of fine needles. While needles for nålbinding can be made of wood or bone, the fine knitting we find from Egypt in the earliest examples so far located, would not be possible until the invention of steel wires. Although some researchers have hesitated to credit the Arabs of North Africa for the beginning of knitting, there certainly is strong circumstantial evidence that knitting needles came about because of the development of steel wire.
Blue (indigo) and white cotton socks from Egypt dating to the 12th century, were knitted toe-up, in the round, and likely with the heel put in last (theoretically so that it could more easily be replaced). You can imagine from the intricate designs that there are many stitches per inch on this example, requiring very fine needles. In her book Ethnic Socks & Stockings, Priscilla Gibson-Roberts gave stitch and row counts for two pairs of similar socks as around 12 stitches/14 rows per inch.
So how do we get from Egyptian socks to socks, hats, gloves and mittens in Europe? With the next early appearance of knitting in Spain preceding the 1492 defeat of the Moors, it seems reasonably likely that knitting spread from North Africa into Spain, and from there, throughout Europe.
Knitted pillow; tomb of Infante Fernando de la Cerda c.1275, in Abbey of Santa María la Real de Las Huelgas, outside of Burgos, Spain.
Knitted items are small, and would have been very easy to transport as part of regular trade, and given how much more practical knitted garments would have been than nålbinding and more fashionable than stitched or wrapped fabric leggings, would easily develop popularity. But there is another way to demonstrate how fashion in particular traveled quickly from place to place — the fashion doll.
77 
77
Not a child’s plaything, the fashion doll was a way for both seamstress and fashionable ladies (particularly royalty early on) to share the latest trends. These doll, known as “Pandoras” were particularly wide-spread in the French court, and were used from Renaissance times to the 19th century when paper patterns began to be produced. They were considered so important that in times of war, some countries issued special “passports” so that the dolls could continue to be sent to other countries despite other types of commercial embargoes.
I’ve not found any examples of fashion dolls that feature knitted garments, but it is interesting to see how clothing was such an important aspect of commercial trade, and allowed innovation to swiftly and readily travel from place to place. It could be argued that the Barbie doll continues to play this role, even with the deluge of fashion information coming from magazines and the web. The lust for current fashion has a long and interesting history!