The Vesper, also known as the Vesper Martini, was invented by author Ian Fleming for his iconic British secret agent, James Bond. The drink first appeared in Fleming’s Casino Royale, which was published in 1953, the cocktail being named for the fictional double agent (and Bond love-interest) Vesper Lynd.
When Bond orders his signature drink from the bartender, he provides strict instructions, which leaves little ambiguity in how to prepare the cocktail: “A dry martini. One. Three measures of Gordon’s, one of vodka, half a measure of Kina Lillet. Shake it very well until it’s ice-cold, then add a large thin slice of lemon peel.”

Référence : https://www.liquor.com/recipes/vesper/