Ten years ago, lost to drugs and alcohol, Karen Little Thunder moved back to the Rosebud Indian Reservation in South Dakota, where, she said, she saved her own life by reconnecting to her Lakota heritage, particularly the legacy of her great-great grandfather. He was Little Thunder, a Lakota leader and a contemporary of Crazy Horse, whose life spanned several decades central to the history of the tribe — from the battles it fought across the Great Plains to its resettlement on reservations.

“He was a great leader who always had the greasiest tepee door, because he was generous and was always feeding people,” she said.

Little Thunder, described by one trader as “six feet or more in height, handsome, with a commanding bearing and superior intelligence,” led a band of Sicangu Lakota that lived along the Platte River, which runs east to west across what is now central Nebraska. He rose to prominence in 1854, after United States Army soldiers shot his predecessor Conquering Bear over a dispute involving a “ten-dollar cow that had wandered into a Lakota encampment from a Mormon wagon train,” said Peter Gibbs, a retired curator of the Native American art collection of the British Museum, who has done research on the Lakota and has taught at a university on the reservation....