"It's hard to say when people first began tying knots because the earliest cord would have been made of organic material (hair, sinew,plant fibre) that has long since decomposed. However, archaeological evidence such as holed beads and wear marks on artefacts suggests that knots were used as far back as the Pleistocene period, the time of ice ages and woolly mammoths (2.5 million to 11,700 years ago), And the use of knots could well be even more ancient than this."
(Houghton et al, Play the Forest School Way, Wakins, London, 2016)