The Irish presence in America dates back to colonial times, when a handful of immigrants came to the New World for greater economic opportunity.

Ireland was governed by Great Britain until 1948, when 26 of its 32 counties seceded to form the Republic of Ireland (the six remaining counties are still part of the U.K.). While under British rule, many Irish were unable to own land or their own businesses.

Mass migration from the island nation, though, didn’t begin until the United States itself had been independent from Britain for some 60 years, when the Potato Famine or “Great Hunger” of Ireland began. The cause of the famine was a blight caused by a pathogen that led to potato crops in the country failing in successive years, from 1846 through 1849.

While the Irish relied heavily on potatoes as a source of food, most farmers on the island were tenant farmers, and their British landlords exported to England and Scotland other crops grown in Ireland (as well as beef, poultry and fish), food that could have helped many Irish survive the famine.

Facing starvation and hopeless poverty, many Irish left for America at this time. However, when they arrived in cities like Boston (and New York, Philadelphia and elsewhere), they came with few skills, other than subsistence farming. As a result, many of them took on low-paying factory work, and found themselves living in what quickly became the slums of these cities—neighborhoods such as East Boston, for example.

To make matters worse, many of these new arrivals were ostracized for religious reasons: Boston, like much of America, was still largely a Protestant nation in the mid-19th century, and most of the immigrants from Ireland were Catholic.

Established society in cities like Boston viewed the Irish as violent alcoholics (hence the phrase, “Don’t get your Irish up”) and labeled them with slurs like “mick.” Those who were wealthy enough to employ Irish servants referred the men as “paddys” and the women as “bridgets.”

Catholic churches in cities such as New York and Philadelphia were burned by anti-Irish mobs, and an entire political party—the American Party—was formed to promote “traditional American ideals.”

By the 1860s, though the Irish were not viewed by many as true Americans, they were nonetheless able-bodied. As a result, as the Civil War broke out, many male Irish immigrants were drafted from Boston, New York and other cities to fight for the Union Army.

While their service offered a welcome paycheck, the conflict was a particularly brutal one, and many were killed or suffered serious injuries on the front lines. In 1863, the brutal violence of the New York Draft Riots killed at least 119 people; many of the rioters were Irish.

Although the Irish were still not embraced by America’s upper-crust society in the years after the Civil War—classified ads for employment reading “Irish Need Not Apply” were still common—they began to enter local politics in the cities in which they lived.

In 1884, for example, Hugh O’Brien became the first Irish-Catholic mayor of Boston. And, notably, the grandson of Irish immigrants to Boston, Joseph P. Kennedy, rose through the ranks of the Democratic Party in the first half of the 20th century, becoming the first head of the Securities and Exchange Commission (SEC) under President Franklin D. Roosevelt as well as U.S. ambassador to Great Britain.

Of course, Joseph Kennedy’s sons—John, Robert and Edward—would all achieve local and national political prominence, with John F. Kennedy elected to the presidency in 1960 and Edward “Ted” Kennedy serving in the U.S. Senate from 1962 until his death in 2009.

Indeed, as the family history of the Kennedys illustrates, Irish immigrants and their descendants were gradually assimilated and accepted into American life, particularly as immigrants from eastern Europe and Asia followed them.

And today, with some 23 percent of Boston’s population claiming Irish ancestry—and many holding positions of power and influence in politics, society and industry—the city retains its place as a center of Irish-American culture and history.