Sherman, commanding general of the Army, and General Philip Sheridan, commanding the Division of the Missouri, designed the campaign as a three-pronged advance intended to trap the non-reservation Lakota and Cheyenne in the Powder River and Bighorn country and force them onto reservations.

Crook’s column — the one Buffalo Calf Road Woman and her brother encountered at the Rosebud — came from the south, marching up from Fort Fetterman in Wyoming.

Terry’s column, which included Custer’s Seventh Cavalry, came from the east, marching west from Fort Abraham Lincoln in Dakota Territory.

Gibbon’s column came from the west, marching east from Fort Ellis in Montana.

The plan assumed that the three columns would converge on the hostile camp in a coordinated fashion, cutting off any avenue of escape.

What it did not adequately account for was the intelligence-gathering advantage that the Lakota and Cheyenne scouts had over any of the Army’s columns.

The warriors knew where Crook was.

They knew where Terry and Custer were.

The Army, operating with inferior scouts in terrain that favored the people who had grown up in it, was largely blind to the exact location and — crucially — the size of the encampment they were moving toward.

The Rosebud fight removed Crook’s column from the equation entirely.