Olives are the fruit of a tree that today can be found as nearly 2,000 separate cultivars within the Mediterranean basin alone. Today olives come in a huge variety of fruit sizes, shape and color, and they are grown on every continent except Antarctica. But olive history and domestication is a complicated one.
Olives in their native state are virtually inedible by humans, although domestic animals like cattle and goats don't seem to mind the bitter flavor. Once cured in brine, of course, olives are very tasty. Olive wood burns even when wet; which makes it very useful. It is likely that the original use of olives was for the oil, which is virtually smoke free and can be used in cooking and lamps, and in many other ways.
The olive tree (Olea europaea var. europaea) is thought to have been domesticated from the wild oleaster (Olea europaea var. sylvestris), at a minimum of nine different times. The earliest probably dates to the Neolithic migration into the Mediterranean basin, ~6000 years ago.
Propagating olive trees is a vegetative process; that is to say, successful trees are not grown from seeds, but rather from cut roots or branches buried in the soil and allowed to root, or grafted onto other trees. Regular pruning helps the grower keep access to the olives in the lower branches, and olive trees are known to survive for centuries, some reportedly for as much as 2,000 years or more.
The first domesticated olives are likely from the Near East (Israel, Palestine, Jordan), or at least the eastern end of the Mediterranean Sea, although some debate persists about its origins and spread. Archaeological evidence suggests that the domestication of olive trees spread into the western Mediterranean and North Africa by the Early Bronze Age, ~4500 years ago.
Olive wood samples have been recovered from the Upper Paleolithic site of Boker in Israel. The earliest evidence of olive use discovered to date is at Ohalo II, where ca 19,000 years ago, olive pits and wood fragments were found. Wild olives (oleasters) were used for oils throughout the Mediterranean basin during the Neolithic period (ca 10,000-7,000 years ago). Olive pits have been recovered from the Natufian period (ca 9000 BC) occupations in Mount Carmel in Israel. Palynological (pollen) studies have identified olive oil presses by the early Bronze Age (ca 4500 years ago) in Greece and other parts of the Mediterranean.
Scholars using molecular and archaeological evidence (presence of pits, pressing equipment, oil lamps, pottery containers for oil, olive timber and pollen, etc.) have identified separate domestication centers in Turkey, Palestine, Greece, Cyprus, Tunisia, Algeria, Morocco, Corsica, Spain and France.
Important Archaeological Sites Sites
Archaeological sites important to understanding the domestication history of the olive include Ohalo II, Kfar Samir, (pits dated to 5530-4750 BC); Nahal Megadim (pits 5230-4850 cal BC) and Qumran (pits 540-670 cal AD), all in Israel; Teleilat Ghassul (4000-3300 BC), Jordan; Cueva del Toro (Spain).
Sources and Further Information
Angiolillo A, Mencuccini M, and Baldoni L. 1999. Olive genetic diversity assessed using amplified fragment length polymorphisms. TAG Theoretical and Applied Genetics 98(3):411-421.
Besnard G, and Bervillé A. 2000. Multiple origins for Mediterranean olive (Olea europaea L. ssp. europaea) based upon mitochondrial DNA polymorphisms. Comptes Rendus de l'Académie des Sciences - Series III - Sciences de la Vie 323(2):173-181.
Breton C, Terral J-F, Pinatel C, Médail F, Bonhomme F, and Bervillé A. 2009. The origins of the domestication of the olive tree. Comptes Rendus Biologies 332(12):1059-1064.
Breton C, Pinatel C, Médail F, Bonhomme F, and Bervillé A. 2008. Comparison between classical and Bayesian methods to investigate the history of olive cultivars using SSR-polymorphisms. Plant Science 175(4):524-532.
Elbaum R, Melamed-Bessudo C, Boaretto E, Galili E, Lev-Yadun S, Levy AA, and Weiner S. 2006. Ancient olive DNA in pits: preservation, amplification and sequence analysis. Journal of Archaeological Science 33(1):77-88.
Liphschitz N, Gophna R, Hartman M, and Biger G. 1991. The beginning of olive (olea europaea) cultivation in the old world: A reassessment. Journal of Archaeological Science 18(4):441-453.
Marinova E, van der Valk J, Valamoti S, and Bretschneider J. 2011. An experimental approach for tracing olive processing residues in the archaeobotanical record, with preliminary examples from Tell Tweini, Syria. Vegetation History and Archaeobotany:1-8.
Terral JF, Alonso N, Capdevila RBi, Chatti N, Fabre L, Fiorentino G, Marinval P, Jordá GP, Pradat B, Rovira N et al. 2004. Historical biogeography of olive domestication (Olea europaea L.) as revealed by geometrical morphometry applied to biological and archaeological material. Journal of Biogeography 31(1):63-77.