The Spanish conquest of Mexico provides the context for this unit, designed for use with students in grades 9-12. It is intended that students will learn about the process of writing history and ways of assessing various historical accounts, and background about the Spanish conquistadors and the vanquished Aztec Indians. The unit contains four lessons. The first lesson teaches students that writing about a historical event, even from an eyewitness point of view, is quite difficult and often problematic. In the second lesson students learn the history of the Spanish conquest through a slide presentation of Indian and Spanish art. The third lesson teaches students that bias can affect historians' ways of seeing, and that one ought to study (if possible) historical texts written by various authors in order to acquire a better sense of historical events. Finally, a fourth lesson is provided for teachers to evaluate student progress. It is suggested that the lessons could be used in world history or language arts Background reading and recommended resources; and (3) Model curriculm standards. (DB)