Period 1 runs from 1491 to 1607 - from the eve of European contact to the founding of Jamestown. It exists to explain what the Americas were like before Europeans arrived, and what happened when three worlds met.

North America in 1491 held hundreds of distinct societies. They differed because they adapted to different environments, and the CED groups them by region:

• In the Southwest, the spread of maize 玉米 cultivation northward from present-day Mexico supported permanent settlement, advanced irrigation 先进灌溉, and greater social complexity.
• In the Great Basin and the western Great Plains, dry conditions produced largely mobile lifestyles 流动性生活方式.
• In the Northeast, the Mississippi River Valley, and along the Atlantic seaboard, societies developed mixed agricultural and hunter-gatherer economies 农业与狩猎采集混合经济, which favoured permanent villages.
• In the Northwest and present-day California, abundant ocean resources allowed settled communities without farming.

The pattern to hold on to is adaptation 适应: the environment shaped the society, and the society reshaped the environment.

European exploration was driven by a search for new sources of wealth 新的财富来源, expanded trade routes, and the spread of Christianity 基督教. Spain and Portugal moved first, and Spain's American empire followed.

Two changes made the voyages possible: improvements in maritime technology 航海技术, and more organised methods of financing trade, especially the joint-stock company 股份公司, which spread the risk of a voyage across many investors.

The Columbian Exchange 哥伦布大交换 is the transfer of plants, animals, people, and diseases between the Americas and the rest of the world. It is the single most important development of Period 1, because almost everything else follows from it.

Moving east to Europe: American crops such as maize and the potato 马铃薯 raised nutrition and helped drive European population growth 欧洲人口增长. American silver 白银 reshaped global trade.

Moving west to the Americas: European animals, crops, and - decisively - epidemic disease 流行病. Populations with no prior exposure suffered catastrophic mortality, and this demographic collapse 人口锐减 accompanied and enabled Spanish conquest.

Spain built an economy that needed labour it did not have.

The encomienda system 委托监护制 granted Spanish colonists the right to extract labour from Native American communities to support plantation-based agriculture and mining 采矿. When that labour collapsed with the population, Europeans turned elsewhere: traders partnered with some West African groups who already practised slavery to forcibly extract enslaved people, beginning the Atlantic slave trade 大西洋奴隶贸易.

Spain then organised the resulting society formally. The caste system 种姓等级制度 defined the status of every group - Europeans, Native Americans, Africans, and people of mixed ancestry - and fixed rights and obligations by category.

Europeans and Native Americans held divergent worldviews 不同的世界观 on religion, gender roles, family, land use, and power. Two ideas about land were especially incompatible: European private property 私有财产 against Native American systems of shared use.

The early years were shaped by mutual misunderstanding 相互误解. As European demands on land and labour grew, Native peoples resisted 抵抗 - through accommodation, alliance, trade, and armed conflict.

Contact also started an argument inside Europe. Extended contact with Native Americans and Africans fostered a debate among European religious and political leaders about how non-Europeans should be treated and what rights they held - a debate that produced justifications for conquest as well as criticisms of it.

Every AP question about Period 1 is really a question about causation 因果关系 or context 时代背景.

• Contextualization 情境化 means placing a development in the broader circumstances that produced it. Period 1 supplies the context for almost every later question about colonisation.
• Causation asks what produced a change and what followed from it. The Columbian Exchange is the clearest chain in the whole course: disease caused demographic collapse, which caused a labour shortage, which drove the Atlantic slave trade.

Worked example (a real AP exam question). The 2023 exam set the long essay "Evaluate the extent to which the growth of transatlantic trade changed British North American colonial society." Period 1 is not the answer to this question, but it earns the contextualization point that opens it: "Transatlantic trade grew out of the Columbian Exchange begun after 1492, which linked the Americas, Europe and West Africa in a single Atlantic system and established the plantation agriculture and coerced labour that later colonial trade depended on." Notice the shape: Evaluate the extent to which wants a thesis that takes a position on how much, and the context sentence must connect to the prompt rather than simply describe an earlier period. A paragraph of unconnected background earns nothing.

• Period 1 is short but supplies context for later questions. Learn it as the origin of the Atlantic system, not as a list of dates.
• The strongest causal chain to memorise: disease → demographic collapse → labour shortage → encomienda → Atlantic slave trade.
• Name specific regions when describing Native societies. "Native Americans farmed" is too general; the Southwest, Great Basin, Northeast, and Northwest each had a distinct adaptation.
• Keep the Columbian Exchange two-directional. Answers that only describe what Europe gained miss half the concept.
• Encomienda is a labour system, not a land grant, and the Spanish caste system is a social hierarchy defined by ancestry.
• For any prompt, identify the task verb first: describe, explain, compare, or evaluate the extent. Each earns points differently.