The burial pit at La Chapelle-aux-Saints was first found in 1908, containing the remains of a man with spinal deformities. An initial misinterpretation of his bones gave rise to the popular legend of the dim-witted, hunched and shuffling Neanderthal.
But over the years, a more careful analysis of his burial site, and the discovery of apparently intentional grave sites elsewhere in Europe, suggested that Neanderthals had a greater capacity for reverence and caring than previously thought.
The report in the Proceedings of the National Academy of Sciences is based on 13 years of research at an excavation site in southern France.
Researchers have now ruled out the possibility that the cave floor under the man -- who was old by Neanderthal standards and may have been in his late 30s or early 40s -- was a natural formation, indicating it must have been dug, said the report in PNAS.
The remains of three more individuals have also been found nearby, though it is unclear whether these two children and one adult were related to, or even the contemporaries of the 50,000-year-old buried elder, said lead researcher William Rendu of France's National Center for Scientific Research (CNRS).
The pit in which his bones lay was made of soft limestone and clay. In nature these rock formations are found horizontally, though the section under his body was nearly vertical, he explained.
"The pit does not have any natural origins, it doesn't fit with any natural phenomenon. The only other explanation is a human origin," said Rendu.
Just who the old man was remains a mystery, but researchers think he must have been an important person, at least to the group of Neanderthals with whom he lived.
Without workable teeth, others likely chewed food for him. His disabled right hip and several broken and fused vertebra indicate he could not move around on his own, said Rendu.
"He was able to live a long time, aided by other members of his group," said Rendu.
"This group of Neanderthals showed a high level of conscience for others," he added.
"If they had wanted to just get rid of this man's body, they could have left it outdoors in nature, where carnivores would have quickly eaten it up. Instead they dug a hole more than a meter (yard) deep using the tools that they had, such as stone or wood or pieces of bone."
While the good condition of the bones suggest he was rapidly interred, the packed sediment around gravesite took a long time to excavate, suggesting it took the man's circle quite some effort to dig it and pack the earth in around the body, Rendu said.
"All this shows that they took a long time to do something that was not essential to their survival but simply to protect the body of this man," said Rendu.
The cause of the man's injuries has been a source of debate over the years, and some experts have questioned whether the burial was truly intentional.
"It's good that they found the remains, but I don't think they needed to resolve the burial issue," said Milford Wolpoff, a paleoanthropologist at the University of Michigan.
"It's like asking whether your Ford was made in Detroit."
Wolpoff said there is ample evidence of burial, language, paint-mixing, and more among Neanderthals, particularly in the last five years.
Adam van Arsdale, a paleoanthropologist at Wellesley College, agreed that the notion of intentional burial should come as no surprise."That research might be able to demonstrate that by re-examining La Chapelle-aux-Saints, a specimen initially recovered more than 100 years ago and one that is a big part of our understanding of 'classic' Neandertals, is more noteworthy," he said.
"It is nice to see a demonstration that hard work and methodological rigor can help recover some of the evidence that was thought to be lost."
The latest round of excavation work began in 1999, and also involved experts from the University of Bordeaux and Archeosphere, a private research firm.