OF OBVIOUS TRUISM , obvious . It dates from the mid-fifteenth century, by a paremiological character, comic and ridiculous, a half-prophet hermit who responded to the name of "Pero Grillo", created by a writer who signed as "The Evangelist" and who appears in his work "Prophecy" where he said "The first day of January to come will be the first day of the year. . . " . It evolves in literature and then in real life until it becomes the expression we know today. For example, "he died when he lost his life" is a truism.