The skull of the Archanthropus was according to Aris Poulianos found by another villager, Christos Sariannidis in 1960, hanging at the wall about 30 cm (12 in) above ground, where it was held by sinter. Aris N. Poulianos states, that "early estimates at the time placed the age of the hominid remains to around 70,000 years". The Petralona skull, its lower jaw missing and completely "encrusted by brown calcite soon after the death of the individual" was estimated to be about 700,000 years old by Dr. Aris Poulianos, head of the excavation team since 1965. He announced that "the date was based on analyses of the cave’s stratigraphy and the accumulated sediments". In 1981, the age of the Petralona skull deduced by Poulianos was investigated and the protocol published in the Nature journal. The scientists involved used electron spin resonance measurements of the calcite encrustation and of bone fragments and dated the age of the skull to between 160,000 and 240,000 years. However, Poulianos states that his excavations in the cave since 1968 provide evidence of human occupation from the Pleistocene era. The Petralona hominid, specifically, was located in a stratigraphic layer containing the highest amount of tools and traces of habitation. Poulianos claims that the age of the overall layer is approximately 670,000 years old, based on electron spin resonance measurements. Other researchers point out, that contextual animal fossils "found with it are known elsewhere from approximately 350,000 years ago". In 1987 researchers announced that the cranium can't be older than 620.000 years after palaeo-magnetic and mineral magnetic studies of the cave's sediments.
