We take for granted now that socks are stretchy, but for most of human history socks were stiff like any other fabric without any elastic threads as part of the fabric blend.

This paper proposes that the bone needles, especially those with three holes, could have been used to make fabrics using the nålbinding technique. With this technique, many items could have been made without sewing, as it creates a very stretchy fabric, which would have been particularly useful for socks and other garments. To test our hypothesis, we conducted an experiment to create fabric using copies of Roman bone needles. Bone needles were very common, and their occurrence could be explained by use of the nalbinding technique to produce fabrics both in the familia and in textile workshops.

https://www.academia.edu/38693060/Bone_needles_and_textile_production_in_the_Roman_time_a_new_proposal