In time, researchers determined that Apidima 2, the more complete of the two skulls, belonged to a Neanderthal.
Researcher Katerina Harvati and her colleagues, who focus on reevaluating the existing fossil record with cutting-edge dating techniques, were invited to study the Apidima fossils.
Prof Harvati believes they were wiped out by environmental factors - which could have include climatic events and pressure from Neanderthals.
But humans migrated out of Africa at different times and different numbers and inhabited different parts of the world.
The researchers were surprised to find all of the signatures of an early member of the Homo sapiens family in the Apidima 1 skull.
"Apidima 2 is about 170,000 years old".
The new finding suggests that our direct ancestors tried repeatedly to move into Europe and Asia, where other early human species already had settled, before finally securing a lasting homeland there, several experts in human origins said.
A new scientific analysis of the two skulls, found during archaeological excavations in the Apidima cave in Greece's Mani peninsula in the late 1970s, suggests that modern humans dispersed out of Africa much earlier than previously believed.
But the latest findings, in no way, can exclude the possibility that H. sapiens and Neanderthals coexisted in southeastern Europe more than 2 lakh years ago and occasionally interbred also.
The best explanation, said study co-author Rainer Grun, a geochemist at Griffith University in Australia, is that "Apidima 1 must come from quite a different environment originally, before it was deposited at the site".
But this narrative has grown ever more hard to sustain because of a range of new fossil discoveries, improvements in their dating and genetic evidence. Until now, the earliest fossil evidence for modern humans outside Africa was from the Misliya cave in Israel, where scientists had found a jawbone dated between 194,000 and 177,000 years old. But they didn't form a single population with a coherent pattern of behavior before they left the continent.
But the skull discovery in Greece suggests that Homo sapiens undertook the migration from Africa to southern Europe on "more than one occasion", according to Eric Delson, a professor of anthropology at City University of NY. Genetic evidence from Siberia and recently Tibet has identified a new hominin species - the Denisovans - that shared a history of interbreeding and interaction with Neanderthals.
"But Neanderthals also had to make way".
Adult male cranium "H. naledi" from Lesedi chamber, Naledi, South Africa.
Scientists claim to have identified the earliest sign of our species outside of Africa with the recovery of a chunk of skull from a cave in southern Greece.
This emphasizes that our explanations for population dispersals need to take into account the context of major environmental change and the opportunities and challenges that went with it. The ever-increasing complexity of the evidence we now have means there is no simple reason for hominin dispersal or replacement. This will enable us to explore the nature of their interactions and not just narrate their consequences.
The study says that a skull found in Apidima Cave from 1978, a Cliffside cave on Greece's southern coast, represents the oldest Homo Sapiens outside Africa.