This article is about literary use of the phrase. For 1917 painting by Paul Klee, see Ab ovo (painting). For biological alternative to spontaneous generation, see Omne vivum ex ovo.
Ab ovo is Latin for "from the beginning, the origin, the egg". The term is a reference to one of the twin eggs from which Helen of Troy was born. The eggs were laid by Leda after Zeus, disguised as a swan, either seduced and mated with or raped her, according to different versions. Had Leda not laid the egg, Helen would not have been born, so Paris could not have eloped with her, so there would have been no Trojan War.[1]
^Helen of Troy: From Homer to Hollywood. John Wiley & Sons, Ltd. Chichester, West Sussex, U.K.