The Pilgrims who arrived in Massachusetts in 1620 came to find religious freedom. In the seventeenth and eighteenth centuries, large numbers of African men and women were brought as slaves to work on large plantations in the South. Immigrants from northern and southern Europe came in the early nineteenth century to escape poor economic conditions at home. Later in the nineteenth century, the first immigrants from China came as contract laborers to build the railroads connecting East and West. In the twentieth century, political and economic refugees arrived from Asia, Eastern Europe, and Latin America. Indeed, the United States has seen immigrants come from many different parts of the world, and they have come for many different reasons. Their ability to adjust to life in their adopted land has depended on several factors.