RALEIGH - A woolen flag with cotton stars flew the night Gen. Thomas "Stonewall" Jackson caught a bullet in the arm -- a quiet witness to one of history's great accidents.

You can see it inside a case on the third floor of the N.C. Museum of History, hanging over a Confederate ammunition chest recovered from a Johnston County farm: the flag carried by the regiment that inadvertently shot the man who was arguably the South's No. 2 general.

The museum just bought the flag for a price Curator of Military History Tom Belton would describe only as a bargain.

Any price would be puny for such a find, he said, calling the flag one of the greatest acquisitions in his 30-year career. No matter what you feel for the rebel soldiers who carried it -- pride, disdain, boredom -- the flag can light the imagination.

"It's the flag that was flying over the regiment that mortally wounded Stonewall Jackson," said Tom Walsh, the New Jersey professor who sold it. "It opens up all sorts of what-ifs."

The flag came to the 18th North Carolina Regiment late in 1862. Those troops came mostly from Bladen, Robeson and New Hanover counties, and they had already slogged through some of the Civil War's bloodiest battles, including Sharpsburg -- or Antietam in the North .

By then, Jackson had become Gen. Robert E. Lee's most trusted lieutenant, a mercurial and deeply religious eccentric nicknamed for "standing like a stone wall" at the First Battle of Bull Run -- or First Manassas, to a Southerner.

But on the evening of May 2, 1863, Jackson rode out to scout Union lines at Chancellorsville. He had just led the twilight attack that crushed the right flank of the Union's powerful Army of the Potomac, an audacious strike by Lee's far smaller Army of Northern Virginia.

When Jackson returned from his reconnaissance, the 18th North Carolina mistook his party for federal cavalry and fired into the dark woods, striking Jackson, who died eight days later.

The major who gave the order to fire -- Wilmington native John Decatur Barry -- never lived it down. He is said to have died of a broken heart at age 27, just two years after the war.

"It was just bad luck," Belton said. "Jackson of all people should know you don't ride into the lines at night unannounced."

Union troops captured the 18th regiment's flag the next day, and it disappeared.

Normally, Confederate flags taken in battle went straight to the U.S. War Department. The N.C. History Museum houses several such samples, all given a stenciled number to mark their time in the North.

But the 18th's flag has no such stencil. No one knows for sure what happened to it after the war, and Walsh isn't eager to shed much light.

More than likely, Walsh said, the New Jersey colonel who captured the flag kept it and passed it secretly to his family as a war trophy.

By the time Walsh discovered it, as a college student and Civil War buff in Manhattan in 1975, its owner thought the squarish rebel battle flag with the X-shape St. Andrew's cross was a loaded and troublesome possession -- more an image problem than a historical curiosity.

"It came to me through somewhat murky circumstances," Walsh said. "I can't really tell you a whole lot about it. It was the mid-'70s, and a lot of the major cities in the country had exploded in racial violence, and this was a Confederate flag in New York City."

The flag has actually been on loan to the museum for more than a decade and spent several years on display before disappearing into storage.

But both Belton and Walsh are happy to see it hanging back in the museum, in the home state of the men who died carrying it.

You look at it and imagine the Civil War without those shots fired at Chancellorsville, if Jackson and the flag had made it north to launch another flank attack at Gettysburg two months later.

Then you move down the hall to consider other relics.