OLEA PRIMA OMNIUM ARBURUM EST
The olive is number one among trees

Throughout the south-eastern basin of the Mediterranean, in the Mesolithic period, olives were crushed by hand using a round stone in small stone cavity mortars.
A paste was obtained, sealed off by olive branches arranged like a crown. This was then placed on a large flat stone and other stones were piled on top. The liquid produced flowed into a ring-shaped cavity and then into the containers below on the bottom of which it deposited, leaving the lighter oil to float.
This mortar and press system was used for thousands of years.
The British Museum in London houses the Vulci amphora on which is depicted an olive picking scene: two men, from below, are striking the branches with poles; another, on the tree, is beating down the olives with a stick and a fourth man, on his knees, is collecting the olives off the ground and placing them in a basket.
Ancient Roman experts (Marrone and Pliny) were against beating with a stick because they considered it detrimental for the tree and the olives: better use a ladder and your hands (picking) and in those areas where the quality of the oil is a paramount factor, this is the system still in use today.