New York City history is endlessly fascinating, entertaining and relevant to today’s issues. In his book, An Unlikely Union: The Love-Hate Story of New York’s Irish and Italians, Paul Moses, a professor of journalism at Brooklyn College, recounts the history of two long-established immigrant groups that were so often in conflict.

The Irish immigrants who arrived in America throughout the potato famine years of the 1840s were the first big wave of poor refugees. They faced anti-Catholic bigotry and clung to their faith which was an integral part of their identity. Over time, they would establish unions, become a powerful force in the NYPD, and dominate politics in major cities.

When the Italians began arriving in New York City in large numbers around 1880, they faced fierce opposition from the Irish who resented their working for less money and longer hours. And although they shared the same faith, Italians were viewed as superstitious because of their devotion to saints, which was expressed in the staging of elaborate feasts. Irish pastors tried to accommodate their growing Italian communities by offering them services in the basement of their churches, but Italian pride would not have it. The stalemate led to the building of churches to serve Italians and other new immigrant groups, not only in New York but other major cities.

There was also growing anti-immigration sentiment that posited the idea that Italians and eastern Europeans were morally unfit to be Americans. Of course, the same argument was made about the Irish. Eventually, this attitude would result in a 1924 federal immigration law that blocked Italians and southern and eastern Europeans from coming to America.

After WWII, proximity and social interaction with each other paved the way for marriages in large numbers. The changing attitudes are depicted in the Oscar-nominated film, Brooklyn (based on the book by Colm Tóibín), when Tony Fiorello brings Ellis Lacey, recently arrived from County Wexford, to his family home for dinner. “We don’t like Irish people,” his little brother Frankie blurts out. He then offers a decades-old explanation about the Irish guys in the neighborhood beating up the Italians while the Irish cops look the other way. Despite this, Tony and Ellis's love blossoms.

Moses said it was important for him to get the facts right since he is half Italian on his mother's side and his wife, Maureen, is Irish. He credits the New York Public Library research collections as essential to his book.

The book demonstrates that long-simmering ethnic conflicts can fall away and yield to friendship and even love, when people interact as equals.