In fact, we were starting back to Fort Laramie, regarding the business at hand as finished, when a scout arrived at our camp and reported the massacre of General Custer and his whole force on the Little Big Horn.
This massacre occurred June 25, 1876, and its details are known, or ought to be known, by every schoolboy.

Custer was a brave, dashing, headlong soldier, whose only fault was recklessness.
He had been warned many times never to expose a small command to a superior force of Indians, and never to underestimate the ability and generalship of the Sioux.

He had unbounded confidence, however, in himself and his men, and I believe that not until he was struck down did he ever doubt that he would be able to cut his way out of the wall of warriors about him and turn defeat into a glorious and conspicuous victory.
The news of the massacre, which was the most terrible that ever overtook a command of our soldiers, was a profound shock to all of us.
We knew at once that we would all have work to do, and settled grimly into the preparations for it.
Colonel Stanton, who was with the Fifth Cavalry on this scout, had been sent to the Red Cloud Agency two days before.

That night a message came from him that eight hundred warriors had left the agency to join Sitting Bull on the Little Big Horn.

Notwithstanding instructions to proceed immediately by way of Fort Fetterman to join Crook, General Merritt took the responsibility of endeavoring to intercept the Cheyennes and thereby performed a very important service.
For this job the general selected five hundred men and horses.