The article reflects upon the process of the training of teachers at public schools in the State of Sao Paulo in the field of Religious Education. The main target of the training was to develop an attitude of tolerance through historical study of Religion in the sense of the mankind’s common cultural heritage. After having summarized the approach of Roger Chartier as theoretical reference the author gives some examples of how religion should be understood as historical construction. The final part discusses the practical consequences that this understanding has for religious education at public schools.