LONDON — It began with a fight, or the threat of one. In Greek mythology, when the pugilistic god Poseidon claimed ownership of the region of Attica, he plunged his trident into the ground and unleashed a salt water spring to symbolize his power as god of the sea. The goddess Athena disputed his claim by planting an olive tree there, saying that it represented peace and prosperity, and the furious Poseidon challenged her to single combat.

Zeus intervened, and asked the other gods and goddesses to settle the matter by deciding who had given them the better gift. All of the gods voted for Poseidon and the goddesses for Athena, but as Zeus abstained, the women’s votes outnumbered the men’s by one, and Athena won. As patron of Attica, she lent her name to its biggest city, Athens, and her gift, the olive tree, has been a symbol of peace ever since.

Not that it is alone. From white doves and rainbow stripes, to angels, broken rifles and two-fingered salutes, countless images have served as peace motifs over the centuries. A new book, “Signs for Peace: An Impossible Visual Encyclopedia,” compiled by the Swiss-born graphic designer Ruedi Baur and his wife, the sociologist Vera Baur Kockot, presents hundreds of images of them through the ages. As you would expect of a “Visual Encyclopedia,” their book does not tell the design histories of each peace symbol, but demonstrates the various ways in which the emblems have come to convey the same message to people from diverse cultures and different eras.