Let a broad wooden chopping block represent the high plain, the altiplano of Mexico; imagine hacking at one half of it with a sharp cleaver until it is grooved and pocked. That fractured surface resembles Mexico’s central highlands, where most Mexicans have lived for millennia. The most severely shattered southern end of the Mexican landscape encompasses Oaxaca, whose rugged topography has isolated its original inhabitants behind high ridges and yawning barrancas for untold generations. In their seclusion, they developed separate tongues and hierarchical societies that viewed outsiders with suspicion and hostility, as odd-speaking, barely human barbarians from across the canyon or behind the mountains. When the Spanish conquerors arrived in Oaxaca, they found a region divided among hundreds of separate subtribes, speaking 16 main languages broken down into scores of mutually unintelligible dialects. The Oaxacans’ own divisions, as much as Spanish horses and steel, led to their quick downfall. The Spanish merely added their own layers atop the existing divisions—of territory, language, caste, class, and wealth—that continue to shape both Mexico and Oaxaca to the present day.