A special exhibit, Treason of the Blackest Dye: The True Story of Arnold, André, and Three Honest Militiamen, will open Saturday, September 19 at The Peekskill Museum. The free exhibit highlightsne of the most remarkable chapters in the Revolutionary War, an event filled with intrigue, betrayal and chance circumstances that, had it unfolded differently, might have resulted in America’s defeat. Curated by Char Weigel of the non-profit organization Revolutionary Westchester 250, the exhibit highlights Benedict Arnold’s treasonous plans and the surprise capture of British Major André in Tarrytown. The exhibit combines historical artifacts and exact facsimiles of original documents along with contemporary depictions, often re-imaginings, of the event.
On the morning of September 26, 1780, large bold letters in American General Nathanael Greene’s orderly book decried “Treason of the blackest dye” as news of Benedict Arnold’s betrayal reached his encampment in Tappan. That treason had begun to unravel days earlier, on September 22, when Benedict Arnold secretly met with British spy John André in Haverstraw. Arnold gave André plans to guide the British attack on West Point, papers that André concealed in his boots for his journey through Westchester County. André’s goal was to give the plans to British troops in New York City, forces poised to attack West Point. Instead, André was captured in Tarrytown on September 23rd by three local militiamen, exposing Arnold’s plot. General George Washington would famously say in despair, “Arnold has betrayed us. Whom can we trust now?”
In honor of the nation’s Semiquincentennial, this exhibit highlights the role the “boot papers” played at a pivotal moment in the Revolutionary War. Exact facsimiles of the papers (courtesy of the New York State Archives) and pages from Greene’s orderly book (courtesy of the U.S. Military Academy Library) are displayed. The exhibit includes a replica of the Fidelity Medal awarded by a grateful Congress to one of the captors, Isaac Van Wart, along with period pieces. Contemporary re-imagining of the story is highlighted through costumes and original cast photos from the popular AMC Series Turn: Washington’s Spies and other objects.
Peekskill Museum Board member Tim Warn refers to the Peekskill area as the “Alpha and Omega”—the beginning and the end—of Benedict Arnold’s treason.
This regional significance is rooted in two key historical events: Peekskill is where General George Washington initially gave Arnold command of West Point, and the Hannock House in Verplanck is where Washington later presented medals to the three men who captured Major André.
RW250 Vice President Char Weigel commented, “Myths and legends about Andre’s capture have proliferated over time, including misinformation about the captors – local militiamen John Paulding, Isaac Van Wart, and David Williams. This exhibit helps correct the record while exploring a moment when the outcome of the war may very well have hung in the balance.” Weigel continued, “RW250 originally curated and produced a version of this exhibit in 2024. Although over 9,000 people viewed the exhibit at that time, we have been repeatedly asked to stage the materials again for the 250th Commemoration. The Peekskill Museum is the perfect setting and partner to do that.”
In conjunction with the exhibit, Weigel will speak on The Treason Cruise – The Sunset Days of Benedict Arnold, a two-hour sunset cruise offered by R.M.S. Cruises leaving the Fleishmann Pier in Peekskill promptly at 3:30. “I’m excited to be able to share new research on the last week that we thought Benedict Arnold was an American. And it will be so unique to have the point of view that many of those involved would have had at the time,” Weigel said.
The Peekskill Museum is located at 124 Union Avenue in Peekskill. The free exhibit will be open Saturdays from 1 to 4 pm and Thursdays 2 to 4 pm starting on September 19 and by appointment.
