"The mosaic floor of an ancient synagogue in the small island of Aegina, near Athens, probably dating from 400 BCE, the ruins of a synagogue in the island of Delos (near Mykonos), a 5th Century BCE " menorah " and a " lulav " carved on marble, found in the Ancient Agora of Athens (adjacent to Acropolis), an inscription dated 300 B.C. saying " Moschos, son of Moschion the Jew " found in Oropos (small coastal town between Athens and Boeotia) are only a few of the relics that witness the fact that Jewish presence in Greece has been in existence for over 2.400 years and maybe more. "
Found here.
It would be laughable but...