Uto-Aztecan language of Mexico, which continues to be spoken by more than a million modern Mexicans in various markedly divergent dialects. Nahuatl was the language of perhaps the majority of the inhabitants of pre-Conquest central Mexico, including Tenochtitlán (now Mexico City), the capital of the Aztec empire. Soon after the Conquest in the 1520s, Nahuatl began to be written in a Spanish-based orthography, and an abundance of documents survive from the colonial period, including annals, municipal records, poetry, formal addresses, and The History of the Things of New Spain, a remarkable compendium of Nahua culture compiled by Indian informants under the direction of the Franciscan friar Bernardino de Sahagún (1499-1590)