In the Florentine Codex, Sahagún wrote numerous introductions, addresses "to the reader", and interpolations in which he expresses his own views in Spanish. In Book XI, "The Earthly Things," he replaces a Spanish translation of Nahuatl entries on mountains and rocks to describe current idolatrous practices among the people. "Having discussed the springs, waters, and mountains, this seemed to me to be the opportune place to discuss the principal idolatries which were practiced and are still practiced in the waters and mountains."