Spanish explorer Hernan Cortes encountered the Aztecs in 1519 and conquered them in 1521, claiming their empire for Spain. He then destroyed the Aztec capital city of Tenochtitlan and rebuilt a Spanish city in its ruins. In this lesson plan, it is the year 1527 and an Independent Counsel has been chosen by the College of Cardinals of the Catholic Church to determine a policy for the Church toward future exploration, conquest, and conversion of the native people of Mexico. The lesson asks students to represent either the Spanish or the Aztecs, whose cases will be argued to the Special Counsel. The Spanish will want to present arguments supporting the conquest. The Aztecs will want to present arguments objecting to the conquest. Students are provided with background information, detailed instructions, on-line and print resources, and reflection questions. The teacher's notes explain the unit's correlation to history/social science and language arts standards, suggest day-by-day teaching strategies, provide an extensive resource list, and include a model for writing a legal brief. (BT)