Kitto's Popular Cyclopedia of Biblial Literature
It is more than probable that the olive was introduced from Asia into Europe; and though it continues to be much cultivated in Syria, it is yet much more extensively so in the south of Europe, whence the rest of the world is chiefly supplied with olive-oil.
Kitto, John, ed. Entry for 'Olive-Tree'. "Kitto's Popular Cyclopedia of Biblial Literature". https://www.studylight.org/encyclopedias/eng/kbe/o/olive-tree.html.