The Yaqui are known for having waged the most determined, enduring, and successful resistance against forced colonization. In fact, they’re the only Native American tribe that has never officially surrendered to either the Spanish colonial forces, the Mexican government, or the United States.

But while they may have won back their land, they didn’t exactly come out on top. During the early 20th century, much of the Yaqui tribe had been captured and sold to plantations. But slavery wasn’t their rival’s only goal. Yaqui women were forced to marry Chinese men—and the reason why is utterly disturbing.