When the National Park Service named its downtown Charleston property “Liberty Square” more than a decade ago, there was little talk of irony behind that name.

The urban park at the eastern tip of Calhoun Street was envisioned as a gateway to the Park Service’s new Fort Sumter Visitors Education Center, as well as the neighboring South Carolina Aquarium. Its original design contained mostly low-lying tablet markers with quotations from American presidents and other statesmen about liberty and freedom.

Today, the park contains something more — additional historic information that shows this site wasn’t always synonymous with those two words.

One of the new wayside markers discusses how this property once was Gadsden’s Wharf, a bustling commercial node at Charleston’s northern end and the primary entry point for African slaves imported into the city during the final quarter century of the nation’s legal slave trade.

The marker explains that approximately 260,000 African slaves were imported through Charleston before the legal trade ended in 1807 — that’s 40 percent of all African slaves brought into what is now the United States.

“The liberty we talk about in the 21st century is not the liberty granted to everyone 200-300 years ago,” said Michael Allen with the National Park Service. “Having a conversation puts it in context. So much of our history ties back to colonial days.”

Tim Stone, superintendent of the Fort Sumter National Monument, said the recent work was done to identify the property more closely as a National Park unit.

Other new markers explain more about the life of two historic figures already honored at the park — the late blacksmith Philip Simmons, who designed its large wrought iron entrance gate, and the late Septima Clark, a civil rights pioneer who is honored here with a fountain. And new banners lead visitors from the street to the aquarium and the boats to Fort Sumter.

“We hope it will become much more of an urban oasis where people can come and reflect,” Stone said. “Our hope is that people who come here say, ‘This is a National Park.’”

The new signs, particularly the one about Gadsden’s Wharf, also provide an interesting complement some of the original markers, including one by Charles Sumner. He was the Massachusetts Senator almost beaten to death on the Senate floor by a South Carolina congressman five years before the Civil War began. This is his quote:

“Where Slavery is, there Liberty cannot be; and where Liberty is, there Slavery cannot be.”

Reach Robert Behre at 937-5771.