When Spanish priests arrived in what is now California almost 250 years ago, they established a string of missions stretching from San Diego to the hills north of San Francisco—all built by forced Indigenous labor. Tens of thousands of Native Americans died from disease, malnourishment, and maltreatment during the mission period, which lasted until the 1830s.

By then, California’s Indigenous population had been devastated—including the Ohlone, or Costanoan, people, whose lands once included much of the San Francisco Bay Area. More than 8000 Ohlone perished between 1776 and 1833; from a precolonization population of approximately 30,000, there were fewer than 100 Ohlone left by the 1920s.