On September 16, 1777, a convoy of wagons traveled 75 miles from Philadelphia to Allentown, Pennsylvania, with an escort of 200 members of the North Carolina and Virginia cavalries. The journey took nine days. At its end, men lifted their precious cargo from layers of potato sacks: twelve bells, including what would later be known as the Liberty Bell.

The British were coming to Philadelphia, and Pennsylvania’s Congress (a separate body from the Continental Congress) didn’t want the invaders taking the bells. They stayed hidden in an Allentown church basement until the summer of 1778, when the British occupation of Philadelphia ended. The bells’ costly bronze metal could have been recast as weaponry, but of far greater value was their sound, a music that carried history, authority, urgency and celebration.

East London’s Whitechapel Bell Foundry Ltd., a company nearly five centuries old, cast many of these colonial voices, including the 12 bells stashed during the Revolutionary War. In a statement released on December 1, the Foundry announced that within the next six months, it would stop its operations on Whitechapel Road, its home since 1738. Owner Alan Hughes, whose family has owned the foundry for more than a century, has sold the property and is considering “the future direction, ownership, and location of the company.”

It's an abrupt shift for a company that's been in business since approximately 1570—and perhaps even earlier. Through the centuries, the foundry has sent bells from Saint Petersburg to Sydney and welcomed generations of the royal family to witness its craftsmanship. In London alone, its handiwork tolls from Westminster Abbey, St. Paul’s Cathedral, and the Palace of Westminster.

The foundry, which declined to be interviewed for this article, told the Wall Street Journal that the decision is the result of “the deterioration of business conditions over many years.” Demand for large church bells is down and costs are up: In 2014, Hughes said that a major bell project could cost as much as £250,000 (over $316,000).

Though the foundry is perhaps best known for casting Big Ben (the bell that rings from the Palace of Westminster's iconic tower), it also helped create the most famous sounds of 18th-century America. It sent at least 27 bells to the colonies during the 1700s alone. A document at Christ Church, Philadelphia, where Benjamin Franklin and other forefathers worshiped, lists a 1702 bell made for the church as the earliest. Fifty years later, the Liberty Bell (first called the State House Bell) arrived, and then, in 1754, a peal of eight bells for Christ Church. Other bells made their way to churches in Williamsburg, Virginia, Charleston, South Carolina, and New York City.

In 1751, Pennsylvania statesman Isaac Norris II commissioned Whitechapel’s most famous American bell to hang from the State House (now Independence Hall). Upon arrival from London, the “State House Bell,” as it was then called, cracked during a sound test, so Philadelphia bell founders Pass and Stowe melted and recast it.

The State Bell became the “Liberty Bell” when 19th-century abolitionists adopted it as a symbol of their cause. Gary Nash, professor of history at UCLA, says that “bell worship predated flag worship." The bell “was by far the one material thing that Americans identified with,” he writes—in part because of the seven national road trips it took to promote national solidarity between 1885 and 1915. After the Civil War, writes Nash, the bell became a symbol of national reconciliation. At each stop on its 1885 trip through the South, he adds, “people surged forward to touch, stroke, or kiss the bell.”

Though the Liberty Bell became a powerful symbol of national unity, it's as famous for its fragility as for its strength. Though it's not entirely certain how the bell became damaged, the foundry suspects its brittle metal may have cracked when rung while in contact with its frame or fittings. Regardless of the reason, the Liberty Bell has not tolled for over 100 years.

The foundry has used the same bell founding technique since the 16th century. For each bell, workers craft two molds from “loam”—a mixture of animal hair, sand, clay, recycled loam, manure and water. The inner mold, “the core,” and the outer mold, “the cope,” are baked to harden, inscribed, coated with graphite and clamped together. Bell metal, an alloy of copper and tin, is heated to over 2,100 degrees Fahrenheit and poured into the mold. When the bell cools, craftsmen break the mold, “skirt” or smoothen the edges, and tune it.

A few blocks away from the Liberty Bell, what some call its “sister bell” regularly rings in the Christ Church steeple. It is called “the tenor” because it is the largest in the peal cast by Whitechapel for the church in 1754. At slightly over 2,000 lbs, it shares the same specifications as the Liberty Bell. When this bell cracked during the winter of 1834, the church sent it back to London for recasting. According to Bruce Gill, a Christ Church vestryman and local historian, this bell’s ring “is the closest we’ll ever get to what the Liberty Bell sounds like.” In the 18th century, the Liberty Bell and the Christ Church bells rang together, most notably on July 8, 1776, when their toll announced the first public reading of the Declaration of Independence.

“A bell was a pre-modern communication device,” says George Boudreau of La Salle University, author of Independence: A Guide to Historic Philadelphia. “Bells were the way the community expressed itself, its political urgency, its faith.” Even today, he points out, bells around the world “express the necessary act of a people,” encouraging them to celebrate when a pope is elected or mourn when a leader has died.

Neil Ronk, senior historian and tour guide for Christ Church, says the eight bells in the 18th-century church steeple have seen America at its best and its worst. He often takes visiting students and families to the back of the sanctuary to touch and occasionally ring the 1702 bell. It's one of just 13 of the 27 bells sent by Whitechapel Bell Foundry to America in the 1700s that still survives.

“There is nothing more fun than having an auditory and tangible history,” says Ronk. When students realize they are hearing the same bell that Thomas Jefferson heard, says Ronk, they feel a deeper connection to history. “Bell ringing is a proxy for an idea that is important.”

Perhaps the best example of this sentiment is another from the modern era. In 2002, the Mayor of London and the Archbishop of Canterbury presented the “Bell of Hope,” cast at the Whitechapel Bell Foundry, as a gift to New York in the aftermath of the 2001 tragedy. Every year, on September 11, it rings during a ceremony from the churchyard of St Paul’s Chapel, evoking American history in a way only its most treasured bells can.