 Previously, specialist literature had referred to an age of either 600,000 or 500,000 years on the basis of less accurate dating methods.On October 21, 1907, Daniel Hartmann, a worker at a sand mine in the Grafenrain open-field system of the Mauer community unearthed a mandible at a depth of , which he recognized as of human origin.He was aware of the likelihood of finds, as for 20 years the Heidelberg scholar Otto Schoetensack had asked that the workers at the sand mine be encouraged to look out for fossils, after the well-preserved skull of a straight-tusked elephant had come to light there in 1887.