Period 1: 1491–1607

What this unit covers

The topics below follow the published US History course framework for Unit 1. This unit is worth 4–6% of the exam, so budget your time against that rather than against how long the unit takes to teach.

Lessons in this unit

• Native Societies Before Contact13 min · 3 objectivesExplain how environment shaped the diversity of Native American societies before European contact · Compare the social and economic organization of major culture regions · Connect the spread of maize agriculture to population growth and settlement patterns
• European Expansion & the Columbian Exchange14 min · 3 objectivesIdentify the motives and technologies driving European exploration after 1450 · Analyze the biological and economic consequences of the Columbian Exchange · Explain how the exchange transformed populations on both sides of the Atlantic
• The Spanish Empire & Cultural Encounters12 min · 3 objectivesDescribe the Spanish system of colonization, including the encomienda and casta systems · Explain how labor demands drove the shift toward African slavery · Evaluate competing European justifications and critiques of conquest
• Environment and Native Diversity: Reading the Map as an Argument14 min · 3 objectivesExplain how differences in climate and resources produced different Native social organizations · Compare sedentary and mobile societies without ranking them as advanced or primitive · Use environmental evidence to support a causal claim about social structure
• The Columbian Exchange as a Two-Way Transfer15 min · 3 objectivesTrace transfers in both directions across the Atlantic and their demographic effects · Explain how the Spanish labor and caste systems organized the early colonial economy · Evaluate the Valladolid debate as a contest over the justification of empire

Every term in Unit 1

All 20 terms we publish for Period 1: 1491–1607, with definitions. Reading them through is the fastest way to find the ones you cannot define — then drill those in cram mode until you can produce them without the prompt.

Mercantilism

The belief that global wealth is fixed, so a nation grows rich by exporting more than it imports and holding colonies as sources of raw materials and captive markets.

Columbian Exchange

The post-1492 transfer of crops, animals, people, and pathogens between the Americas and Afro-Eurasia. Significance: Old World diseases killed up to 90 percent of Indigenous populations, while American crops such as maize and potatoes fueled Eurasian and African population growth.

Encomienda system

Spanish grants entitling colonists to Indigenous tribute and forced labor. Significance: the first large coercive colonial labor system in the Americas; its brutality provoked the Las Casas–Sepúlveda debate and pushed Spain toward importing enslaved Africans.

Casta system

Spanish colonial racial hierarchy — peninsulares, criollos, mestizos, mulattoes, Native peoples, Africans — which fixed legal and social privilege by ancestry.

Maize cultivation

Spread north from Mesoamerica and allowed permanent settlement and irrigation in the Southwest. The reason Pueblo societies were sedentary while Great Basin peoples were mobile.

Pueblo peoples

Southwestern societies who built permanent adobe settlements and irrigated maize agriculture in an arid environment — the CED's central Period 1 example of environment shaping society.

Great Plains nomadic societies

Peoples who followed buffalo herds and lived in portable dwellings because the Plains could not support farming with the technology available.

Iroquois Confederacy

Alliance of five (later six) Northeastern nations governed by a shared council — evidence that Native societies had complex political institutions before contact.

Pacific Northwest societies

Chinook and neighbors built permanent villages on abundant salmon and timber without agriculture, proving sedentary life did not require farming.

Bartolomé de Las Casas

Dominican friar who condemned Spanish treatment of Native peoples and argued for their humanity; his critiques fed the Valladolid debate and the "Black Legend".

Juan Ginés de Sepúlveda

Argued Native people were natural inferiors whose conquest was justified. Opposed Las Casas at Valladolid (1550–51), the era's central debate over Native humanity.

Requerimiento

Document read aloud in Spanish to Native peoples demanding submission to Crown and Church, which legally justified war if they refused. A ritual of legitimation, not communication.

Joint-stock company

Investors pooled capital and shared risk and profit. Financed English colonization without Crown money — why English colonies began as commercial ventures.

Treaty of Tordesillas (1494)

Papal-brokered line dividing new lands between Spain and Portugal, giving Portugal Brazil and Spain most of the Americas.

Mission system

Spanish religious settlements aimed at converting and controlling Native populations, combining evangelism with labor extraction and cultural suppression.

Mestizo

A person of mixed European and Native descent. Their number in Spanish America, versus their rarity in English colonies, reflects sharply different settlement patterns.

Valladolid debate (1550–51)

Las Casas against Sepúlveda before a royal junta on whether Native peoples were rational humans with rights. Evidence that Europeans contested the justification of empire among themselves.

Black Legend

The account of Spanish cruelty in the Americas, drawn largely from Las Casas's own writings, which England and the Dutch turned into anti-Spanish propaganda to justify their own colonization.

Three Sisters agriculture

Interplanted maize, beans and squash: the corn supports the bean vines, the beans fix nitrogen, the squash shades out weeds. A high-yield system that supported Eastern woodland towns.

Demographic collapse

Native population losses reaching an estimated 90% in some regions within a century of contact, driven by smallpox, measles and influenza — the labor shortage that drove the turn to enslaved African labor.

What examiners penalize here

• On the exam, resist writing about Native Americans as one uniform group. The CED wants you to argue that **environmental variation produced social variation**. Naming a specific region and its adaptation (irrigation, bison hunting, salmon fishing) earns the point.
• When a prompt asks about the *shift* to African slavery, argue causation explicitly: Native depopulation + rising profits + disease-resistant, trade-accessible African labor. Naming all three links reads as sophisticated analysis, not just description.
• A Period 1 short answer almost always wants **environment → social structure**, in that direction. If your sentence names a region and a resource but never says what *changed socially* as a result, you have written half an answer. Finish the causal chain every time.

Practice US History

Our practice bank is drawn from across the whole course rather than filtered to one unit, which is closer to how the exam asks anyway — it will not tell you which unit a question is testing.

Questions about this unit

All 9 units of AP United States History

1. Unit 1 · Period 1: 1491–1607
2. Unit 2 · Period 2: 1607–1754
3. Unit 3 · Period 3: 1754–1800
4. Unit 4 · Period 4: 1800–1848
5. Unit 5 · Period 5: 1844–1877
6. Unit 6 · Period 6: 1865–1898
7. Unit 7 · Period 7: 1890–1945
8. Unit 8 · Period 8: 1945–1980
9. Unit 9 · Period 9: 1980–Present