Valencia and other descendants of lynching victims are now casting attention on one of the grimmest campaigns of racist terror in the American West: the lynching of thousands of men, women and children of Mexican descent from the mid-19th century until well into the 20th century.

Some victims were burned alive. Other mobs hanged, whipped or shot Mexicans, many of whom were U.S. citizens, sometimes drawing crowds in the thousands.

Lynchings have long been associated with violence against African-Americans in the American South. Lynchings of Hispanics have faded into history with less attention. Often, they have been portrayed as attempts to exercise justice on behalf of white settlers protecting their livestock or claims to land.

But a new movement is underway to uncover that neglected past. It has unleashed discussions about the scramble for land or mining claims that frequently influenced these lynchings, as well as the traces of such episodes in resurgent anti-Latino sentiment and the question many parts of the United States are confronting: Who gets to tell history?

“The conquest of the West is still simply a tale of incredible progress for many Americans,” said Monica Muñoz Martínez, a professor of American studies at Brown University.

“But despite the unwillingness to recognize these lynchings as a tragedy, or even recognize them at all, momentum is building to finally reckon with these events,” said Muñoz Martínez, who was raised in Texas and is a co-founder of Refusing to Forget, a group committed to increasing awareness about state-sanctioned violence against Latinos in Texas.

Texas, which enshrined white supremacy in its 1836 constitution when Anglo slaveholders seceded from Mexico, had by far the most episodes of mob violence against people of Mexican descent, according to William D. Carrigan and Clive Webb, historians who have documented such cases.