From the vantage of 2016, the military career of Seth Eastman has all but vanished from history while his artistic achievements loom large.

Eastman was commandant of Fort Snelling from 1841 to 1848 — his second tour of duty to what was then a quiet wilderness outpost. His new position allowed time to pursue his passion for painting the Dakota Sioux and Ojibwe people who lived nearby.

The sketches he did then remain among the most revealing records of that era in Minnesota and the nation’s history.

“He learned the Dakota language, knew this culture was disappearing, and felt impelled to record it,” said Marla Kinney, a curatorial fellow who researched a show of 18 Eastman watercolors that opens Saturday at the Minneapolis Institute of Art.

The watercolors were painted in 1849-55, after Eastman returned to Washington, D.C., as illustrations for “Indian Tribes of the United States,” a six-volume study commissioned by Congress and written by Henry Rowe Schoolcraft, the explorer who established the origin of the Mississippi River in northern Minnesota.

In Eastman’s day, Fort Snelling overlooked a wide landscape of rivers, prairies and woodland inhabited mostly by nomadic Dakota Sioux and Ojibwe people. The Indians camped in the hills and valleys near the confluence of the Mississippi and Minnesota rivers or lived in villages on the shores of nearby lakes. Statistics are scarce, but a tally taken in the early 1830s found some 8,000 Dakota in the area and about 300 soldiers at the fort.

Eastman’s watercolor of Ojibwe women gathering wild rice in a birchbark canoe is the earliest known record of the subject. Different styles of Dakota housing appear, one of traditional conical tepees and another of elm-bark lodges that look like Euro-style homes with rectangular door openings, peaked roofs and shady platforms on which kids are seen playing games while animal pelts dry in the sun. Similar platforms appear in “Guarding the Corn Fields,” though as perches from which the Indians beat pans and wave their arms to scare off a flock of birds bent on eating the grain.

Given the lively details in “Spearing Muskrats in Winter” (bent grasses, cattails, snow-bogged pine trees), Eastman surely must have hiked out onto a snow-covered marsh with the buckskinned hunters whose packs bulge with rodent carcasses as they thrust their long spears into the muskrat mounds.

Family ties

The watercolors were given to the museum in 2014 by the W. Duncan and Nivin MacMillan Foundation. The show, which will remain on view through Jan. 8, also includes three lithographs on Indian themes by others: an 1842 portrait of a Chippewa chief by Charles Bird King, and two scenes by George Catlin.

While Eastman’s paintings are not obviously autobiographical, their lively, close-up descriptions of Indian lives and customs convey a respect and affection rare for the time. Their intimacy hints at an acceptance and access perhaps linked by his complicated family ties to the Dakota people.

A native of Maine, Eastman (1808-1875) was fresh out of West Point and just 22 when he arrived in Minnesota for the first time in 1830. Trained as a mapmaker and illustrator, he had a classical education in art that served him well as he set about sketching his new terrain.

He married a 15-year-old woman, Wakanin ajin win (Stands Sacred), whose father, Cloud Man, was a prominent Dakota chief of mixed French and Indian heritage. They had a child together, Winona (a name that means “firstborn daughter”), also known as Nancy Eastman, who was born in 1832. Shortly thereafter, Eastman was called back to West Point, where he taught drawing until the Army sent him back to Fort Snelling in 1841.

While at West Point, he married an aristocratic Virginia woman who subsequently accompanied him to Minnesota, bore their four children, and became a keen recorder of Indian life and legends. In 1849 she published a book, “Dacotah, or Life and Legends of the Sioux Around Fort Snelling,” illustrated by her husband.

Though his first marriage officially ended with Eastman’s departure, he evidently remained on good terms with his Indian family. His daughter married a Dakota man (Santee Sioux), with whom she had five children. After Winona died while giving birth, her husband took the name Eastman — along with two of their sons, one of whom became a Presbyterian missionary and the other a medical doctor.

Artistry in action

The precision required in Eastman’s training as a mapmaker also honed his eye for details — note the Navajo blanket and feather-garnished fedora on listeners in the “Indians in Council,” and the hut, piles of firewood and metal kettles employed to produce maple syrup in “Indian Sugar Camp.”

Two paintings illustrate traditional stories recorded by Eastman’s Virginia-born wife. “Wenona’s Leap” shows a tiny speck of a woman, distraught over a frustrated romance, about to leap from a bluff overlooking Lake Pepin. “The Falls of St. Anthony” depicts the suicide of Anpetu Sapawin (Dark Day), a woman who, according to legend, paddled over the falls with her infant in despair over her husband taking a second wife.

Other paintings record unusual ceremonies such as the “Beggar’s Dance,” in which dancers cajole the audience to contribute goods for the needy, and “Dog Dance of the Dacotahs,” in which some dancers mimic dog behavior while others dance around a pole supporting the heart and liver of a recently sacrificed beast whose virtues the dancers hope to acquire.

“We’ll never know how accurate Eastman’s paintings were, or how documentary,” Kinney said. “But we know they were intended to be accurate and, in the end, this is our heritage.”