Research suggests that crochet probably developed most directly from Chinese needlework, a very ancient form of embroidery known in Turkey, India, Persia and North Africa, which reached Europe in the 1700s and was referred to as “tambouring,” from the French “tambour” or drum.
In this technique, a background fabric is stretched taut on a fra me. The working thread is held underneath the fabric. A needle with a hook is inserted downward and a loop of the working thread drawn up through the fabric. With the loop still on the hook, the hook is then inserted a little farther along and another loop of the working thread is drawn up and worked through the first loop to form a chain stitch. The tambour hooks were as thin as sewing needles, so the work must have been accomplished with very fine thread.
At the end of the 18th century, tambour evolved into what the French called “crochet in the air,” when the background fabric was discarded and the stitch worked on its own.
(from the Crochet Guild newsletter)