May 4th is often known as "Star Wars Day". It is jokingly said: "May the 4th be with you", in reference to the popular phrase in Star Wars: "May the Force be with you." The phrase dates back to at least 1979, on the day Margaret Thatcher was elected Britain's first woman prime minister. Her party took out a newspaper ad in the London Evening News that said "May the Fourth be with you, Maggie. Congratulations."