It was discovered in February 1936 near Mojokerto (East Java, Indonesia) by a member of an excavation team led by Ralph von Koenigswald.

The authors of the paper, Carl C. Swisher III and Garniss Curtis, argued that this date had wide implications for our understanding of the first human migrations "Out of Africa".

[5] It was eventually classified as Homo erectus just like "Java Man" and the numerous early human fossils that von Koenigswald and others found in Sangiran.

[9] Their rock sample – "hornblende grains from volcanic pumice that appeared to match the filling of the skull" – came from a site shown to them in 1990 by Teuku Jacob, an Indonesian paleoanthropologist who had studied under Ralph von Koenigswald.

[1] Morwood argued that the rock samples Curtis and Swisher dated came from a pumice bed located 20 metres (66 ft) below the one above which the Mojokerto skullcap was found.

[14] In 2006, Australian archeologist Frank Huffman used pictures and fieldnotes from the 1930s to identify the exact site of the excavation and confirmed that the fossil was indeed found between the two layers that Morwood had dated.