In April 1980 Pope John Paul II in a special pastoral letter declared St Francis of Assissi the patron of ecologists and lovers of nature: On the 10th anniversary of this event the author tries to answer the question of what this fact has given to ecology and what essentials the Franciscan movement has brought into the cause of saving the environment. This movement organizes several international seminars, among others in Gubbio during which a special appeal was directed to the political and religious authorities.