From what I gather, it was street food and poor food in and around the mission towns in the Tex-mex borderlands. San Antonio is considered its cultural home, and it is distinctly American. Earliest documented recipes are from Spain in the late 1600s and refer to a Native American stew of venison and chilis.
It became popularized by Texas trail hands and cowboys in the early 1800s as the first "instant trail meal". They pounded dried beef, suet, pepper, salt, and the chili peppers together into a brick or paste. Think of it as hot pemmican. Due to its condensed nature it was very stable, could be made edible simply by adding enough water to hydrate into a soup. It was likely served with camp breads or tortillas, and or beans (likely the origin of the association between chili and beans).
