Until the late 19th century, there wasn’t any such thing as “illegal” or “legal” immigration to the United States. That’s because before you can immigrate somewhere illegally, there has to be a law for you to break.

American immigration didn’t really begin until the late 1700s, when the United States became an independent nation. Before that, Africans had unwillingly entered the Americas as enslaved peoples and Europeans had entered as settlers—which is something totally different. While immigrants are beholden to the laws of the land they migrate to, settlers come to disrupt the current system and implement their own laws, write the scholars Eve Tuck and K. Wayne Yang.

But once the U.S. made its Constitution the new law of the land, immigrants flocked to the country with few restrictions. This didn’t mean that they were welcomed in the “New World.” In the beginning, when immigrants came mostly from northern and western Europe, anti-Irish and anti-Catholic sentiment were rampant. By the mid- to late-19th century, people from southern and eastern Europe as well as China were coming over, and Americans resented the presence of Chinese, Italians, and more Catholics.