Students and faculty at Columbia University have unearthed hidden parts of the school’s history, with myriad connections to slavery in the earliest days of the college.

The Ivy League school is one of a growing number of universities to explore an aspect of the past that many had long preferred to ignore — and to show how integral the slave trade was not only for the Southern states, but for the economy in the North as well.

Protests over race on campuses across the country in the past two years have intensified efforts to answer questions about slavery and its role at colleges founded in the 18th and 19th centuries. Last year, Georgetown University announced efforts to make amends for profiting from the sale of 272 Jesuit-owned slaves in 1838. The research at Columbia did not unearth anything as stark as that, but rather illustrated a time when slavery was so commonplace that its shadow fell on many aspects of daily life.

“From the outset, slavery was intertwined with the life of the college,” history professor Eric Foner wrote in a preliminary report of the findings, first reported by the New York Times.  “Of the ten men who served as presidents of King’s and Columbia between 1754 and the end of the Civil War, at least half owned slaves at one point in their lives.”

The report describes a college firmly rooted in a city that was, in the 18th century, an important trading center with slave ownership and auctions commonplace, and entire shipments of enslaved people arriving on New York wharves from the Caribbean and Africa. Just before the Revolutionary War, almost 3,000 of the city’s 19,000 people were enslaved.

A math professor in the 1760s asked students to calculate profits for three investors in a slave-trading voyage. Many students grew up in homes with slaves and at least one, George Washington’s stepson John Custis, brought an enslaved person with him to college; the man, named Joe, prepared his breakfast each morning. Researchers found dozens of ads for runaways, placed by college leaders, students and others.

The report also describes changing sentiments as the years went on, as the fight for independence led to questions about slavery from people such as Alexander Hamilton, a student and then trustee of Columbia. A prominent abolitionist in the early 19th century, alumnus John Jay II, defended fugitive slaves in court until slavery was abolished in New York in 1827. But most criticism of slavery was much more tempered and “genteel” until the Civil War, Foner said.

William Duer, president of then-Columbia College from 1829 to 1842, also led the Colonization Society of the City of New York, which promoted the idea that slavery was wrong but large numbers of freed former slaves would pose a threat to the country, and that they should be sent to Africa. (In earlier years, he had advertised a girl for sale.)

During the Civil War, Columbia’s leadership supported Abraham Lincoln and an end to slavery.

At some colleges, the questions were sparked by student activists. But at Columbia, Foner was inspired to begin the project after reading a book written by a former student, Craig Wilder, “Ebony and Ivy: Race, Slavery and the Troubled History of America’s Universities,” and talking with Columbia’s president Lee Bollinger about it. He knew Brown University had initiated a high-profile investigation into its ties to the slave trade years earlier, and that other universities such as Harvard were exploring the issue as well.

The president’s office provided funds for student researchers, and Foner and another professor taught seminars in which undergraduates dug through university archives — which were somewhat thin, because the university has had three separate locations in the city, and records apparently were lost and destroyed with each move.

They had an advantage researchers decades ago did not have, though, Foner said, with online database of the slave trade that allowed them to search for vessel owners connected to Columbia.

“It was wonderful working alongside a Pulitzer-prize-winning professor like Eric Foner,doing research,” said Jared Odessky, who graduated in 2015. He was interested to see that slavery was so much a part of life early in the university’s history that it barely registered in documents from the time, and they only found one person so far, Jay, who was really fighting it. It made him and his classmates wonder what things they take for granted that, 100 years from now, people will be asking, “‘Why weren’t students talking about this?'” and made him think differently about student activism.

Ankeet Ball studied Alexander Hamilton, about whom so much has been written that he was surprised to gain new insights. Ball concluded that Hamilton’s childhood on St. Croix, where there were 22,000 enslaved people at the time and just 2,000 white people, made an indelible impression on him and made it impossible for Hamilton to overlook slavery and explained his discomfort with some of the provisions added to the Constitution. Ball wrote, “Hamilton detested the institution of slavery with fervor, but whenever the issue of slavery came into conflict with Hamilton’s central political tenet of property rights, his belief in the promotion of American interests, or his own personal ambition, Hamilton allowed these motivations to override his aversion to slavery.”

Speaking by phone, Ball, who graduated in 2016, said, “This was a hallmark of my time at Columbia. It changed how I viewed Columbia, how I viewed race at Columbia, and put a lot of things in perspective for me. I hope this project continues.

“It’s soul-searching for universities — I think that’s very important.”

Foner said, “I hope all of this will make people realize how central slavery has been to our  history — the North as well as the South. Too many people seem to see slavery as kind of a footnote, an aberration — they don’t quite grasp how absolutely central it was to the settlement of these colonies and the economic development of the U.S. And the racial configurations created by slavery still haunt us to this day.”