source: Wikipedia
A widespread view exists that the first cultivation took place on the island of Crete.
Archeological evidence suggest that olives were being grown in Crete as long ago as 2,500 B.C. The earliest surviving olive oil amphorae date to 3500 BC (Early Minoan times), though the production of olive is assumed to have started before 4000 BC.
An alternative view retains that olives were turned into oil by 4500 BC by Canaanites in present-day Israel Homer called it "liquid gold." In ancient Greece, athletes ritually rubbed it all over their bodies. Olive oil has been more than mere food to the peoples of the Mediterranean: it has been medicinal, magical