Sakakawea had a baby in early 1805, just before setting off with Meriwether Lewis and William Clark.
Her son was named Jean Baptiste.
Why the French name? Because her husband, Toussaint Charbonneau, was a trapper from Quebec.
But Clark, who had “developed a particular affection for the child,” nicknamed him Pomp.
When the party arrived at a large sandstone outcropping in mid-1806, Clark named it “Pompys Tower” and carved his signature and the date into the rock.
The outcropping, now located in the state of Montana, has since been renamed Pompeys Pillar and designated a National Monument.