The world before it was one.

Song China (960–1279) was the world’s most urbanized society. Champa rice from Vietnam fueled population growth; gunpowder, movable type, paper money, and the magnetic compass all originated here. Neo-Confucianism reasserted hierarchy and women’s subordination, while the civil service exam selected officials by merit (mostly from the gentry). Heian Japan adopted Chinese script, Buddhism, and Confucian government before developing distinctive aesthetics. Korea’s Goryeo dynasty synthesized Chinese influences while innovating: Korean movable type predated Gutenberg by two centuries.

After the Mongol sack of Baghdad (1258), Abbasid power collapsed but Islamic civilization expanded. Turkic peoples (Seljuks, Mamluks, Ottomans) became its political backbone. Sufism’s mystical-personal Islam helped spread the faith into Central Asia, India, and West Africa by adapting to local cultures. The House of Wisdom’s preserved Greek texts—Aristotle, Galen, Ptolemy—reached Europe via Cordoba and helped trigger the Renaissance. Mathematicians like al-Khwarizmi (algebra, algorithms) and astronomers like al-Tusi shaped modern science.

The Delhi Sultanate (1206–1526) brought Islamic rule to north India, imposing the jizya tax on non-Muslims but also catalyzing Hindu-Islamic cultural fusion. The Bhakti movement countered with devotional Hinduism accessible across castes—it would echo in Indian Sufi Islam. In Southeast Asia, the Khmer Empire built Angkor Wat (the largest religious monument on Earth); Srivijaya controlled the Strait of Malacca and grew rich taxing Indian Ocean trade. Both were Hindu-Buddhist polities adapting Indian religion to local cultures.

The Aztec Triple Alliance (1428–1521) ruled central Mexico from Tenochtitlán through tribute and human sacrifice. The Inca Empire (1438–1533) stretched ~2,500 miles, knit together by 25,000 miles of roads, terrace agriculture, the mit’a labor draft, and quipu record-keeping. Both were technically literate states without alphabetic writing. North of the Rio Grande, Mississippian Cahokia (~20,000 people c. 1100) was larger than London at the time. Pueblo societies in the Southwest built the cliff dwellings at Mesa Verde and Chaco Canyon.

Mali (c. 1235–1670s) controlled the Trans-Saharan gold trade; Mansa Musa’s 1324 hajj brought so much gold to Cairo that prices crashed for a decade. Timbuktu was a center of Islamic scholarship. Great Zimbabwe (c. 1100–1450) built dry-stone palaces from gold, cattle, and Indian Ocean trade. The Swahili coast (Kilwa, Mombasa) blended Bantu and Arab cultures into “Swahili” through monsoon trade with India and China—Chinese porcelain shards still wash up on Kenyan beaches.

Decentralized feudal Europe was the Eurasian backwater of 1200, rebuilding from the Roman collapse. The Catholic Church and feudal manors organized society. The Crusades (1095–1291) reopened Mediterranean trade and exposed Europeans to Islamic learning. The Black Death (1347) killed roughly a third of Europe but broke the manorial system: surviving peasants demanded wages. By 1400 the Italian Renaissance was beginning—humanism, perspective, recovered classical texts. Europe’s ascent in the next era would build on these foundations.

AP World loves comparison. Be ready to compare: tribute and labor systems (Aztec tribute vs. Inca mit’a vs. Mali gold trade); religious policy (Delhi Sultanate jizya vs. Aztec sacrifice vs. Christian crusade); state legitimation (Mandate of Heaven vs. divine right vs. caliphal succession); urbanism (Hangzhou vs. Tenochtitlán vs. Cordoba vs. Cahokia). The strongest essays cite SPECIFIC features of each side and tie comparisons to causation.