Humans have been using tools to shave hairs and whiskers for over 20000 years. Sharp implements that could cut through hair were very often made from sharpened pieces of bone.
The bronze age saw major developments in the ability to create long lasting sharp edges, but it wasn`t until the 18th Century in Sheffield, England that the modern razor consisting of shaped handles and hollow ground blades started to take shape. Sheffield was a major manufacturer of steel until recently.