Why are oligarchy important to the Sparta's?

Immigration to North America began with Spanish settlers in the sixteenth century, and French and English settlers in the seventeenth century. In the century before the American Revolution, there was a major wave of free and indentured labor from England and other parts of Europe as well as large-scale importation of slaves from Africa and the Caribbean.Although some level of immigration has been continuous throughout American history, there have been two epochal periods: the 1880 to 1924 age of mass migration, primarily from southern and eastern Europe, and the post-1965 wave of immigration, primarily from Latin America and Asia.[1] Each of these eras added more than 25 million immigrants, and the current wave is far from finished. During some of the peak years of immigration in the early 1900s, about one million immigrants arrived annually, which was more than one percent of the total US population at the time. In the early twenty-first century, there have been a few years with more than one million legal immigrants, but with a total US population of almost 300 million, the relative impact is much less than it was in the early part of the twentieth century.The first impact of immigration is demographic. The 70 million immigrants who have arrived since the founding of the republic (formal records have only been kept since 1820) are responsible for the majority of the contemporary American population.[2] Most Americans have acquired a sense of historical continuity from America’s founding, but this is primarily the result of socialization and education, not descent. The one segment of the American population with the longest record of historical settlement are African Americans. Almost all African Americans are the descendants of seventeenth- or eighteenth-century arrivals.[3]Much of the historical debate over the consequences of immigration has focused on immigrant “origins” – where they came from. Early in the twentieth century, when immigration from southern and eastern Europe was at its peak, many old-stock Americans sought to preserve the traditional image of the country as primarily composed of descendants from northwest Europe, especially of English Protestant stock.[4] The immigration restrictions of the 1920s were calibrated to preserving the historic “national origins” of the American population.There u go!