The oldest preserved shoe is 9,000 years old. But research makes clear, the modern shoe can be between 26,000 and 40,000 years old, i.e. already in the Neanderthal Age. This is based upon research – not into shoes, but into feet. The shoes themselves have not been preserved that long.
The small toes – not the thumb – have become weaker in the aformementioned period, says Erik Trinkhaus, physical anthropologist, in the Journal for Archaeological Science. So probably in those days one started wearing real shoes. Toes did not any longer need to be large and flexible for better grip.
In the Northern areas, people already used covers for their feet against the cold, but these are more predecessors of our modern socks, as they did not give any extra support.