Why does a duPont mansion have a stone wall topped with jagged glass shards?

Mending fences might not have been in Alfred I. duPont's nature. 

And that has long been said to be one of the reasons why he built a 10-foot stone wall topped with shards of broken glass to surround his majestic Nemours mansion in Rockland.

Generations of Delawareans who have driven past the stone wall off Del. 141, near the DuPont Co.'s Experimental Station, have long wondered who they are keeping out — or in?

While the shards work like barbed wire, discouraging criminals and the curious, popular lore has it there's an even deeper meaning behind the jagged glass. 

Was this duPont's elaborate way of throwing shade at family members he didn’t like? 

The wall, one of the quirkiest landmarks in New Castle County, if not the state, is said to have represented a longstanding feud among members of the duPonts, Delaware's most wealthy and influential family. 

Alfred I. duPont supposedly said he built the wall with the glass shards around his estate “to keep out intruders, mainly of the name of duPont,” according to Marquis James’s 1941 book "Alfred I. duPont: The Family Rebel."

A slight variation of the quote was repeated in the 1990 biography "Alfred I. duPont: The Man & His Family," by Joseph Frazier Wall.

Was it said in jest? Was it said at all? Maybe. Maybe not.

The legend might be better than the actual truth, but, first some background:

Nemours/Alfred I. duPont Hospital for Children is the legacy of Alfred I. duPont, who with his cousins Pierre S. and T. Coleman duPont founded the modern-day DuPont Co.

Yet, despite the family ties, there was no love lost between the cousins. 

Alfred's strained relations with duPont family members began to simmer when he divorced his first wife, Bessie, who was also his cousin, in 1906. Alfred then cut off contact with her and all of their children except for his eldest, Madeleine duPont.

He further infuriated family when, with a week's notice, he evicted his hated ex-wife, Bessie, from the duPont home at Swamp Hall, off Brecks Lane on the south side of the Brandywine near Hagley.

He threw even more gasoline on the fire when he had Swamp Hall razed.

A possible affair with, and eventual marriage, to Alicia Heyward Bradford in 1907, another cousin, did little to endear him to family members. Alicia Bradford was the ex-wife of duPont's secretary. 

In 1909, duPont, in an effort to please his Francophile new wife, began construction on the Nemours Estate. The mansion was designed to look like Marie Antoinette's Petit Trianon on the grounds of the Palace of Versailles.

At that time, Nemours cost $2 million, more than Andrew Carnegie's 64-room 1901 mansion in New York City. The cost today for duPont would have been $52.8 million. 

Nemours, a 77-room, 47,000 square foot house, was ready for occupancy in December 1910. It was designed by the same architects who created the New York Public Library and the Senate Office Building. It has the largest formal French gardens in North America, a chauffeur's garage housing a collection of vintage automobiles and nearly 200 acres of scenic woodlands, meadows and lawns.

The glass-topped wall that encloses part of Nemours estate was installed around 1915-16, as part of an effort to re-engineer the main entrance to the property, according to Nemours Estate Executive Director John C. Rumm.

Prior to its being built, Rumm said visitors entered via a mile-long driveway that ran from Concord Pike near the Blue Ball Barn and made a series of curves through woodlands before ending alongside Nemours Mansion.

Alfred, concerned with security and privacy, had stonemasons build the wall around the 300 acres that comprised Nemours' main grounds. It concealed the estate from public view and also served to heighten the dramatic “reveal” of the mansion that the new, straight driveway onto the property afforded guests, Rumm said.

Stonemasons used Brandywine granite hewn from the surrounding hillsides for the 10-foot wall that measured about 3,200 running feet.

Rumm said there is no contemporary evidence to support or confirm the quote, attributed to Alfred I. duPont, that first appeared in James’ book and was widely repeated, that he built the wall to keep out duPont family members.

In his book, "Alfred I. duPont: The Man & His Family," biographer Wall says local children were paid a penny apiece for bottles of clear, green and brown glass  that were then broken and set in concrete on top of the wall. Yet, Rumm said, that's also lore that can't be verified.

What is known, he said, is "to the best of our knowledge, all of the glass is original and none has been replaced or added."

The stone wall, with its extreme "decorative" security, actually reflects Alfred’s and Alicia’s design sensibilities and interests in French architecture, Rumm said. It emulates a practice commonplace in medieval France, in which glass-topped walls were built to enclose towns and villages.

The glass works like metal spikes, barbed or razor wire to keep the unwelcome from scaling the walls.

While Alfred planned the house as a symbol of love for his wife, the marriage was not a happy one and the estate, one biographer wrote, became the couple's prison.

Nemours was derided by thrifty duPont family members as ostentatious and the stone wall with the glass shards, and its apparent cost, was deemed "atrociously forbidding," Wall said in his book. 

Pierre S. duPont, with the help of others, eventually voted Alfred off the DuPont Co. board in 1916. Alfred's wife Alicia died in 1920.

DuPont married again a year later to Jessie Ball. By this time, he was deaf and could see out of only one eye after being partially blinded in a hunting accident. He and Jessie lived in Nemours, but also spent much of their time in Florida.

Unlike most of his family members, Alfred I. duPont, who died in 1935, was not buried at the duPont family cemetery.

Rather, he is interred, along with his dog, his wife and his brother-in-law under a 210-foot bell tower on the grounds of Nemours. According to biographer Wall, Pierre S. duPont and other family members came to his funeral.

The wall with glass shards remains to this day.

Nemours Estate, a publicly-accessible mansion, gardens and grounds now occupies about 200 acres in Rockland. Nemours/Alfred I. duPont Hospital for Children, with which it shares a campus, occupies the remaining 50 or so acres.

The estate closed for the season in December. It will reopen for visitors May 1. Go to the Nemours Estate Facebook page or the website, nemoursmansion.org for more information.

"Why is this here?" is an occasional News Journal/Delaware Online feature that looks at the history behind curious objects found throughout Delaware.  

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Contact Patricia Talorico at (302) 324-2861 or ptalorico@delawareonline.com and on Twitter @pattytalorico