The Bighorn River slips from the rocky clutches of the Big Horn and Pryor Mountains, going deep and muddy on the valley plains. Two hundred years ago, John Colter, enchanted by tall grass and great herds of bison, received permission to leave the Corps of Discovery early to hunt and trap the good country along the river. Though the bison and beaver are gone, my 87-year-old grandmother, Mary Ahern Maxwell, who spent her girlhood on a tributary creek called Mountain Pocket, has often told me that the Bighorn Valley holds the best land in all Montana. And this windswept October day, as we drive south toward the mountains, I believe it: Thick grass lines the roadway, the foothills slope down into coulees knotted with chokecherry and wild rose, and though it's as gray as stone, the sky is wide.

Years ago, before my grandmother's family settled down on Mountain Pocket, before Colter, the three bands of the Crow people lived in a vast tepee. One of its corner poles sloped up from the west, at the meeting of the three rivers. Another sat far in the south, where the Bighorn River begins. The third pole was anchored to the east, near South Dakota's Black Hills. And the final pole rested where the Yellowstone gives itself to the Missouri. The fire of that great tepee was here -- along the banks of the Bighorn, in the mountain shadows.

In the late 1850s, a young Crow warrior climbed deep into the Pryor Mountains. There, he did not eat but prayed and paced the mountain. Desperate for a dream, he cut off the tip of his left index finger and beat his wounded hand on a fallen log. As his blood wet the wood, he slumped into a deep sleep. Then a storm rose up, and the young man saw himself as a chickadee sheltered in a high nest. The other birds did not seek the safety of their nests. They flailed against the wind and soon were lost. As the sun split the storm, the young man looked into his dream, far out onto the Plains, where a great herd of buffalo ran. The earth cracked open before them; the buffalo fell into the earth and were gone.

That young man, Plenty Coups -- knowing the buffalo would soon be gone; knowing that against the white men, who were as strong and as violent as the four winds, the Crow must hunker down in their nests -- urged his people to continue the early truce they had made with the United States and proved himself adept at peacetime leadership. He journeyed to Washington, D.C., many times to argue against seizures of Crow land and for fair negotiations. On the reservation, he moved into a frame house and took up farming, began practicing the Catholic faith alongside his traditional beliefs. In 1920, Plenty Coups -- who had once declared, during an earlier attempt to reduce the size of the Crow Reservation, "If you white men put in all your money to buy that land, you would not pay all it is worth. …  I want my country to remain" -- acquiesced to demands from younger Crow leaders and supported the Crow Act, which parceled up the reservation into individual land allotments, a move that preserved its outer boundaries but would lead to complications, because the land allotments could then be sold or leased. As these negotiations came to a close, Plenty Coups was invited to stand with President Harding at the 1921 Armistice Day ceremony at the Arlington National Cemetery. There, Plenty Coups wore beaded buckskin and a headdress of eagle feathers; he brandished his coup stick and laid it on the Tomb of the Unknown Soldier. Though he had been instructed not to speak, Plenty Coups prayed for peace as the coffin was lowered. And he prayed in Crow.

Plenty Coups' aggressive peace-making, a survival strategy philosopher Jonathan Lear has dubbed "radical hope," was formulated to ease his people's transition into a new way of life, a way of life he didn't ask for but was powerless to stop. And, in at least one respect, it worked: Open a map of Montana and you'll see that the Crow Reservation is the biggest in the state; though treaties were bent and broken over the years, the ancient heart of Crow country remains in Crow hands.