Knitting was invented in Egypt during the 12th century AD by nomadic sheep herders who would create fabric through the simple use of knotting wool yarn using straight twigs. The technique had advantages over traditional weaving and allowed any shepherd and his wife to produce a more valuable product instead of just selling their wool. The practice quickly spread from Egypt throughout the Middle East and into Europe. Muslim knitters in Spain started developing a variety of knitting stitches that allowed them to create shaped fabrics, the sock being one of the first knitted items of clothing to be produced.
In 1589, William Lee of Calverton in England invented the first knitting machine which overnight transformed knitted garments into something almost everyone could afford. Knitting is credited with transforming the textile industry and became the precursor to the industrial age.
In China and Japan during the first millennium BC puppets were being intricately carved from wood. Puppets were being used in India by the 11th century as devices to give morality stories a visual impact that words couldn't convey. Puppets have been used to represent good, evil, jealousy, and greed without running the risk of identifying individuals who might exact revenge against the storyteller. In ancient India puppets were constructed from carved sticks, and were often elaborately decorated. Sock puppets were likely invented when knitted socks became more widely in use.
As the puritan movement in England gained momentum, traditional puppetry was banned along with all other forms of theater. During these years in England and France, radicals would organize secret theater shows and used puppets, as they were easier to transport and conceal than sets, costumes, and large bands of actors. Socks and very basic stages made of suspended fabric hung behind a table became a popular way of getting around the ban. It was about this time that the puppet character Punch was created.
After the return of the monarchy and the end of puritan times Punch and Judy, puppets became more commonly associated with glove or hand puppets. Children used discarded socks that could be decorated to mimic a hand puppet.
Recently the term sock puppet is also used to describe a fictitious identity used online to promote a particular point of view or defend a person who is seen as controversial.