The Original Olive Leaf
The olive leaf as a symbol of peace has its roots in the Torah's account of the Great Deluge.
When Noach wished to determine whether the flood waters had subsided he sent a dove outside the ark. When it returned in the evening with an olive leaf in its mouth Noach realized that the waters had indeed subsided.
Our Talmudic Sages say that the olive leaf came from the Mount of Olives where it survived the devastating flood waters since the deluge did not affect Eretz Yisrael.
Thus was born the tradition of associating the olive leaf with peace.