Founded by Franciscan Father Junípero Serra in 1771, the San Gabriel Mission has long been seen as an essential link to California’s past, as well as to the brutality and racism that played a role in the state’s founding.

Considered by historians to be the most important base of operations for the Spanish conquest of California, San Gabriel was the fourth of 21 missions established in the state, and one of the grandest. At its height in 1829, the mission had 50,000 livestock, 160,000 grapevines, and 2,300 fruit trees, said Philip Ethington, professor of history and political science and chair of the history department at USC.

But the church amassed those riches on the backs of the Tongva and other indigenous people, whom the friars forced into labor and coerced into converting to Catholicism and assimilating to their culture.

“It was really a labor camp enforced with whipping and stockades and lots of corporal punishment,” Ethington said.

Thousands are estimated to have died after they were exposed to foreign diseases or suffered other “comorbidities of conquest,” said William Deverell, director of the Huntington-USC Institute on California and the West and a professor of history at USC.

“It’s still a site of faith and worship, but it’s also a site of great sadness,” Deverell said. “Because in that parish ground, within the confines of the church, there are thousands of unnamed indigenous dead below what’s now a small Catholic cemetery.”

Yve Chavez, an assistant professor at UC Santa Cruz, whose ancestors lived at the mission, helped build it and are buried in its cemetery, also described its legacy as complicated.

“On the one hand, the news of today is quite devastating because this is something that our ancestors made,” she said. “Some people might see these as monuments to Catholicism or Spain, but I think it’s important to recognize that this is the product of Native labor.”

Still, she noted, that work was performed under duress and came at an unspeakably high cost.

“The structure itself is a reminder of our ancestors who sacrificed their lives and their labor to make these missions possible,” she said.