A single reckless act raised Trembling Earth (or Earthquake) from a lowly horseholder to a warrior of distinction who represented his people before the Great Father in Washington.

As Colonel McKenney heard the story, the series of events that affected the young brave's life began when a party of voyager on their way to a trading post met a band of warriors from Trembling Earth's village. When a Frenchman refused to share his horse he was murdered by one of the Indians. The rest of the trappers fled to the Yankton village to inform the chiefs and demand the killer be executed.

The ancient code of the Sioux permitted a victim's relative to seek revenge; if no relative was willing, a friend was allowed to take his place.

The tribe laughed when Trembling Earth publicly announced that he would satisfy the honor of the unknown white man, but the boy who had never been on a war party silenced them when he returned with the warrior's scalp.

McKenney claimed that the motivation for Trembling Earth was not pity for the white man he never knew nor to wipe out the stain of dishonor on the village, but simply ambition. The young warrior, he wrote, "grasped at an opportunity, thus fortuitously presented, to emancipate himself from his humble condition."

Evidently, the chiefs were not concerned with Trembling Earth's motivation; not only had a murderer who had endangered their village been executed but more important, the white men were satisfied and the Dragoons from Jefferson Barracks in St. Louis did not appear.

The former horseholder now became "a good warrior" who was sent to Washington in 1837 as a member of the delegation that signed a treaty with their Great Father.

Trembling Earth was stricken in the capital with what McKenney called "a fever," but he refused to cancel the appointment to have his portrait painted. As McKenney wrote, the Sioux was "suffering under the influence of fever" when he sat for the artist. It was finished three days before his death in October 1837.