Although the earliest known samples of knitting date from the 11th century AD, it is thought to have originated long before this. Examples of single needle knitting have been found from as early as 300BC.
According to Wikipedia:
“Knitting is the process of using two or more needles to loop yarn into a series of interconnected loops in order to create a finished garment or some other type of fabric. The word is derived from knot, thought to originate from the Dutch verb knutten, which is similar to the Old English cnyttan, to knot”.
It is thought that knitting spread from the Middle East to Europe along the Mediterranean trade routes. In the 13th century AD Spanish Royal Christian families employed highly skilled Muslim knitters to make garments and household accessories.
Fashions in Elizabethan times created a high demand for fitted stockings. A very important home-based industry grew up in Britain to meet this demand, and the fine woollen stockings were also exported to countries including Spain, Germany and the Netherlands. The advent of various knitting machines led to a decline in hand knitting as an industry. It began to grow as a hobby instead.
The popularity of hand knitting has risen and fallen several times throughout history, largely influenced by social and political conditions. The First World War, the Great Depression, and the Second World War all created a need for people to return to hand knitting garments.
Fashion trends during the 1920s and the 1950s and 60s raised the popularity of knitwear as fashion items. However, the introduction of clothing such as track suits and sweat shirts as alternatives to woollen garments, led to a sharp decline in the hand knitting market.
The good news is that the 21st century has seen a renewed interest in handcrafts and creative hobbies in general. Today there is a huge range and variety of yarns and patterns available, and the internet allows people around the world to connect and share patterns, tips, and ideas.
If you would like to read about the history of knitting please check out these Wikipedia articles.