El General

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Lesson Plan: Recognizing Bias in Historical Accounts

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In this lesson, students will explore the work of historians and learn how to evaluate historical accounts critically. To accomplish these goals, students will analyze the potential biases of two primary sources and one written history, all of which describe the Cristiada, a bloody war that took place from 1926 to 1929 between militant Roman Catholics, known as Cristeros, and the Mexican government ruled by Plutarco Elias Calles.

The lesson features excerpts from El General, a film that looks at the life and legacy of Calles, who was president of Mexico from 1924 to 1928. The film was produced by Calles' great-granddaughter, who uses audio of her grandmother (Calles' daughter), archival footage and modern-day shots of Mexico City to examine Calles' legacy.

Note: This film is in Spanish with English subtitles.

For more information on Mexico's history, please see POV's Timeline: The Life and Career of Plutarco Elias Calles.

POV documentaries can be recorded off-the-air and used for educational purposes for up to one year from their initial broadcasts. In addition, POV offers a lending library of DVDs and VHS tapes that you can borrow any time during the school year -- FOR FREE! Get started by joining our Community Network.

Please visit our Film Library to find other films suitable for classroom use or to make this film a part of your school's permanent collection.

Students will:

  • Recognize that written history reflects an author's interpretation of past events.
  • Analyze video of primary sources to determine potential bias.
  • Evaluate whether a historical account of a conflict in Mexican history favors one side over the other.


SUBJECT AREAS: International, World History


  • Internet access and equipment to show the class online video clips
  • Handout: Viewing Guide (PDF file)

ESTIMATED TIME NEEDED: One 50-minute class period


Clip 1: "Grandmother's Recordings" (length 4:40)
The clip begins at 6:32 with the phrase "My first memories..." and ends at 11:12 when the narrator says, "...they fought for freedom, justice and democracy."

Clip 2: "Everyone Thought My Father Was Anti-religious" (length 3:09)
The clip begins at 40:01 and ends at 43:10 with the statement "I do believe that he was furiously anti-clerical."
Note: Clip 2 contains some graphic imagery. Please preview before using in the classroom.

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  1. Ask students to take a few minutes to describe, in writing, a recent school or community activity that members of the class likely attended. Invite some students to share their descriptions and ask students to take notes on the differences in accounts. Guide students to the realization that any version of an event, no matter how objective it seems to be, is essentially a subjective interpretation of what happened.
  2. Explain that just as students gave different accounts of the activity, historians also interpret the past in different ways. They form conclusions about events after considering diaries, letters, interviews, artifacts and other items. These conclusions always reflect the historians' judgments about potential bias in eyewitness accounts, as well as which details were most and least important.
  3. Help students perform the work of historians by evaluating the biases of two primary sources who share their perspectives on a specific conflict in Mexican history. Distribute the Viewing Guide and familiarize students with its questions. Then, show the two video clips from the film El General and discuss the potential bias that Alicia Calles might have about the events of the Cristiada.
  4. Next, show the class the video clip, "Juan Guitierrez: Original Cristero Soldier" (length: 2:31). Discuss: According to Guitierrez, what government actions caused the Cristiada? Why did he think it was important to fight the government? If Guitierrez were to write a history of the Cristiada, what bias might his account reflect?
  5. Divide students into pairs and ask one student in each pair to assume the role of Alicia Calles and the other to assume the role of Guitierrez. Then, ask students to read a history from the U.S. Library of Congress on "The Calles Presidency" that includes information on the Cristiada. Instruct each pair to discuss whether the piece contains any bias, and then ask each partner to write a paragraph from his or her assigned perspective that evaluates how fairly the piece interprets the events of the conflict.
  6. Collect the two paragraphs from each pair and ask for a show of hands to illustrate how many students think the author of the historical account favored the perspective of the government, how many think the author favored the Cristeros and how many thought the piece provided a balanced perspective.



Students can be assessed on:

  • Thoughtful and complete responses on the Viewing Guide handout.
  • Contributions to partner work and class discussion.
  • The analysis of the paragraph written from their assigned perspective.

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  • Ask students to consider this quote from Calles' last state of the union address in 1928: "History's judgment is always harsh and unjust because the circumstances of the moment are ignored or forgotten." Explain that Calles took office after more than a decade's worth of revolutionary uprisings in which all of the leaders were assassinated. (See POV's Timeline: The Life and Caree of Plutarco Elias Calles for details.) Discuss how those circumstances could have played into Calles' desire to establish and maintain control and institute policies that sought to reduce the power of the Roman Catholic Church. Tell students also to consider the perspectives of writers Cuauhtémoc Medina and Jean Meyer on this topic by showing the related video clips on the POV website. Ask students to write persuasive essays that address whether or not the circumstances of the times justified the events of the Cristiada.


  • Watch El General in its entirety and ask students to write essays that analyze how life in modern-day Mexico is linked to the country's political past. Students should conduct additional research as needed to back up points made in their papers.

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Country Studies. "Mexico."
This website contains the online versions of books previously published in hard copy by the Federal Research Division of the Library of Congress as part of the Country Studies/Area Handbook series. The study of Mexico includes information on its history, geography, society, economy and government.

NewsHour. "Political Timeline."
PBS' NewsHour provides a snapshot of political milestones in Mexico from the overthrow of Jose Porfirio Diaz to the 2006 election. NewsHour also provides a student-friendly article on the 2006 election.

POV. "The Life and Career Plutarco Elias Calles."
The POV website provides additional information that explores Calles' role in Mexican history.

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These standards are drawn from "Content Knowledge," a compilation of content standards and benchmarks for K-12 curriculum by McRel (Mid-continent Research for Education and Learning).

Behavioral Studies

Standard 1: Understands that group and cultural influences contribute to human development, identity and behavior.

Standard 4: Understands conflict, cooperation and interdependence among individuals, groups and institutions.


Standard 10: Understands the nature and complexity of Earth's cultural mosaics.

Standard 13: Understands the forces of cooperation and conflict that shape the divisions of Earth's surface.

Historical Understanding

Standard 1: Understands and knows how to analyze chronological relationships and patterns.

Standard 2: Understands the historical perspective.

Language Arts

Standard 9: Uses viewing skills and strategies to understand and interpret visual media.

World History

Standard 40: Understands the search for peace and stability throughout the world in the 1920s and 1930s.


Cari Ladd, M.Ed., is an educational writer with a background in secondary education and media development. Previously, she served as PBS Interactive's director of education, overseeing the development of curricular resources tied to PBS programs, the PBS TeacherSource website (now PBS Teachers) and online teacher professional development services. She has also taught in Maryland and Northern Virginia.