Pope-emeritus Benedict XVI sees same-sex marriage as “in contradiction with all the cultures of humanity that have followed one another up to now,” in the introduction to a forthcoming book. In his introduction to the book—a collection of his past written works on Europe—the former Pontiff says that the legal recognition of homosexual marriage “signifies a cultural revolution that is oppose to the whole tradition of humanity until today.”

Pope Francis wrote a preface for the book, The Real Europe, which is being released to mark the 50th anniversary of diplomatic relations between the Holy See and the European Union.