The attack took place on Evacuation Day, the anniversary of the departure of British troops from New York in 1783, which was still spiritedly celebrated, particularly among Irish-immigrant Anglophobes, some of whom had joined in the Draft Riots in 1863.

In a book about the attack, “The Man Who Tried to Burn New York,” Nat Brandt quoted a Confederate newspaper in Richmond, Va., which disavowed the plot a week after it was exposed. “If there is any place in the North that ought to be spared, that place is New York,” the editorial said. “Not that its population is overtly friendly to us, but that it is undeniably hostile to Lincoln and his government.”

Still, as Clint Johnson wrote in “A Vast and Fiendish Plot,” while the city’s merchants had believed before the war that what was good for the South was good for New York, “Southerners just could not get past the fact that 40 cents of every dollar of cotton sold went into the pockets of New Yorkers” for shipping costs and interest payments on loans.

Harold Holzer, a Lincoln scholar and the author, most recently, of “Lincoln and the Power of the Press,” said: “It’s hard to know whether this Evacuation Day terrorist plot ever could have succeeded. The arson technology involved was so primitive, and the would-be terrorists so eager to flee from the fires they thought they would be setting (unlike modern suicide bombers, fortunately), that the enterprise was bound to fizzle rather than sizzle.

“But there is no doubt that this was a deadly serious attempt to make New York howl in the same way Sherman was, at that very time, making Georgia howl. It was a plan to strike fear in the hearts of Northern civilians and break their will to fight.”

Eight saboteurs escaped to Canada, but one, Robert Cobb Kennedy of Louisiana, was arrested when he slipped back into the United States en route to Richmond. He was executed at Fort Lafayette in New York Harbor — now the site of the Brooklyn tower of the Verrazano-Narrows Bridge — four months after the plot failed.