Peter Thompson rode with the U.S. Army’s 7th Cavalry at the Battle of the Little Bighorn in 1876 and lived to tell about it.

Because his horse broke down.

Thompson, a Scottish immigrant whose father owned a farm near Blairsville, would have died with Lt. Col. George Armstrong Custer had his mount, which he described as “poor and gaunt” from the rigors of a forced march into the Montana Territory, not given out.

“I was gradually left behind in spite of all I could do to keep up with my company,” he wrote in his account of the battle, published in the Belle Fourche (S.D.) Bee in 1914. “All urging on my part was useless. … My horse was entirely played out.”

Which saved his life.

Custer and the 209 men with him, badly outnumbered by Indian warriors, were wiped out June 25 on what came to be known as Last Stand Hill. Other companies of the 7th Cavalry continued the fight the next day. Thompson, wounded twice, earned the Medal of Honor for bravely bringing water to his wounded and dying comrades.

And yet, the 22-year-old private from Indiana County, recognized for valor under fire, would later come under fire of another sort, accused of cowardice and desertion.

DAVID LONICH and Gerry Schultz believe Thompson’s reputation has been unfairly tarnished.

Lonich, a historian from Donora who wrote “From the Monongahela to the Little Bighorn: Western Pennsylvanians in Custer’s Command” for Western Pennsylvania History magazine, asserts that Thompson was a hero, not someone who scurried away from danger.

“He’s a very, very controversial figure,” Lonich said. “As a historian, it’s important to read those firsthand accounts, but you also have to take them with a grain of salt, especially since he was writing that article years later. But he did go and get water, there’s no question about that. He did a really compassionate and brave thing. To me, that is worth recognizing.”

Schultz, a retired electronics technician for the Burlington Northern Railroad and a resident of Bloomfield, Mont., has made it his mission to defend Thompson since finding a crumpled manuscript — titled “Custer’s Last Fight, The Experience of a Private Soldier in the Custer Massacre” — in a creek bed following a 2007 flood. Thompson wrote the story for friends and family, but it was ultimately published by the Bee and later formed the basis for a book, “Peter Thompson’s Narrative of the Little Bighorn Campaign 1876.”

Schultz began scanning the pages right there in the creek bed, and was mesmerized by Thompson’s account.

“As I read that document, essentially I went through the Battle of the Little Bighorn through the eyes of Peter Thompson,” he said. “So when I got home one of the first things I did was look on the internet, and I find he’s been trashed severely — called a deserter, a liar, a fraud. But when I began to investigate it, I found that’s all based on misinformation. I felt an injustice had been done to Peter Thompson, and I wanted to right the wrongs done to him. There’s virtually no justification for destroying this man. He is a true American hero.”

Schultz has conducted exhaustive research into Thompson’s actions at the Little Bighorn and even portrays him in annual re-enactments at the battlefield. Most of what Thompson wrote lines up with the accounts of other survivors, although one incident he describes opened him up to withering criticism: His claim that he and Pvt. James Watson, whose horse also broke down, spotted Custer at the river, away from his command, not long before his death.

Some argue Custer would never have left his troops, but he often rode on ahead.

“Seeing Custer is not a fabricated story,” Schultz said. “Custer rode off the ridge and went down to the river near where Thompson was. For him to go to the river on a recon was nothing unusual whatsoever. He was always riding out by himself looking over the situation. He did that his entire career.”

THOMPSON FOUND himself on the banks of the Little Bighorn barely nine months after enlisting in the Army.

The Thompson family — father John, mother Agnes and their five children — arrived in the United States from Scotland in 1865 and settled in Banksville, a small community eventually annexed by the city of Pittsburgh. John worked as a coal miner, as did Peter. John later purchased a farm in Indiana County and Peter, reluctantly, was obliged to help out.

“After assisting father on the farm for some years, I took a decided dislike to that kind of work and became anxious to get away from it,” Thompson wrote. “The thought of becoming a soldier took possession of my mind.”

During a trip to Pittsburgh to visit some friends who had just emigrated from Scotland, he found an Army recruiting station and enlisted on Sept. 21, 1875. Thompson was assigned to Fort Lincoln, located on the Missouri River in the Dakota Territory, near present-day Bismarck, N.D. — headquarters of the 7th Cavalry.

That put him on a path to the Little Bighorn and one of the most storied battles in American history.

THE 7TH Cavalry consisted of 12 companies, numbering more than 600 men. They marched west from the Dakota Territory and on the morning of June 25, 1876, discovered what some historians believe was one of the largest encampments of Plains Indians ever, stretching more than three miles along the west bank of the Little Bighorn River — “a truly imposing sight,” Thompson wrote.

Custer split his forces, then led a detachment down Medicine Tail Coulee to attack the village of Lakota Sioux, Northern Cheyenne and Arapaho Indians. But Thompson and Watson, slowed by lame horses, were left behind. They didn’t learn of Custer’s fate until two days later.

With Indians soon “closing in all around,” Thompson and Watson concealed themselves for several hours before finding their way to Maj. Marcus Reno’s command, which had retreated to a position on top of a high bluff, about four miles from Last Stand Hill. The next morning they were besieged by Indian warriors who, under cover of darkness, had climbed up ravines and approached their position.

“We were in a very precarious condition,” Thompson wrote. “The Indians were pouring a shower of lead into us that was galling to the extreme.”

Capt. Frederick Benteen ordered about a dozen men, Thompson included, to charge toward a ravine and clear it of Indians. They advanced through a hail of bullets, one of which struck Thompson.

“As I was entering the mouth of the ravine a volley was fired by the Indians who occupied it and over I tumbled, shot through the right hand,” he wrote.

Dr. Henry Porter attended to Thompson in the field hospital.

“The bullet had gone through his middle finger and removed it and rolled up his arm, so he must have been grasping his carbine with his right hand,” Schultz said. “It lodged in his elbow. He carried that the rest of his life. Whenever you see pictures of him he always has a bent elbow. He no longer could straighten it.”

AFTER PORTER bandaged his wound, Thompson handed his rifle to another soldier; it was useless to him, as he could no longer shoot. But he soon found another way to contribute. Thompson was inspired to become a water carrier after happening upon a mortally wounded friend, Pvt. James Bennett.

“I could see that his days were numbered,” Thompson wrote. “Kneeling down beside him I asked, ‘Can I do you any service?’ He grasped my hand and drew me closer to him and whispered, ‘Water, Thompson, water, for God’s sake.’ Poor fellow, he was past speaking in his usual strong voice.”

Thompson grabbed two canteens and a camp kettle and headed toward the river. Sgt. Daniel Kanipe stopped him en route and tried to dissuade him from going, convinced it was a suicidal venture. But Thompson was undeterred.

Even though he was in pain and his hand had swelled “to a great size,” Thompson began a daring descent down a steep ravine to the water. Bullets whizzed by as he reached the river, and one grazed his head.

“He looked around and saw nobody, so he took off from the cover of the ravine and ran toward the river,” Schultz said. “He scooped up water with a camp kettle — he said he scooped up more sand than water — but a volley of about 20 rifle shots came at him. At that point he received a head wound. Years later his daughter Susan described it as a three-inch furrow in his scalp, above his right ear. That was about as close as you can come to gathering your wings.”

Thompson made three more trips to the river that day. What haunted him for the rest of his life was the memory of the cries of wounded comrades so desperate for water they were willing to pay to be “first in line” for a drink.

“The offers of money,” Thompson wrote, “was painful to hear. ‘Ten dollars for a drink,’ said one. ‘Fifteen dollars for a canteen,’ said a second. ‘Twenty dollars,’ said a third man, so the bidding went on as at an auction.”

The heat was oppressive and Thompson had lost so much blood from his wounds that he was compelled to take a break after his second trip to the river.

“He lay down in the shade of a horse as his arm and hand were so swollen and he was sick and dizzy,” wrote Susan Thompson years later in a family history. “A horse stepped on his (uninjured) hand after while, arousing him painfully.”

MORE PAIN came in later years, long after the battle.

Thompson worked at the Homestake gold mine in the Black Hills of South Dakota for 18 years and then operated a ranch in Alzada, Mont. He was, by all accounts, a model citizen and was often called on to settle local disputes, so respected was his judgment.

But there were those convinced Thompson had cut and run at the Little Bighorn. He encountered some of his harshest critics in Arlington, Va., in 1921, when Medal of Honor recipients were invited to join a procession to the just-completed Tomb of the Unknown Soldier. Thompson wound up leaving the event in disgust. Some Little Bighorn survivors in attendance questioned his heroism and, worse, accused him of desertion because he had failed to follow Custer into battle. Not that Thompson could have, given the condition of his horse.

“I’m sure it was very painful for him not to be believed,” Lonich said. “They sort of resurrected the story that he was a coward, that he was deserting, trying to get away. He was so hurt by that that, unlike others who sought to be buried in military cemeteries when they died, he chose to be buried out there in the miners’ cemetery,” in Lead, S.D.

Thompson remained bitter over his treatment until the moment he drew his last breath, on Dec. 3, 1928.

So was this one-time resident of Indiana County a hero, as Lonich and Schultz contend, or a coward? Consider this: When Thompson completed his five-year Army hitch, his discharge papers included handwritten notations from his commanding officers, Col. S.D. Sturgis and Capt. Henry Jackson, attesting to his “excellent” character.

Even more telling are two words included on the citation that accompanied his Medal of Honor. Thompson, it noted, was being recognized for “conspicuous bravery.”