During the assault on Chapultepec Castle on September 13, 1847, he refused what he felt was a "bad order" to withdraw his troops. Confronted by his superior, he explained his rationale, claiming withdrawal was more hazardous than continuing his overmatched artillery duel. His judgment proved correct, and a relieving brigade was able to exploit the advantage Jackson had broached. In contrast to this display of strength of character, he obeyed what he also felt was a "bad order" when he raked a civilian throng with artillery fire after the Mexican authorities failed to surrender Mexico City at the hour demanded by the U.S. forces. The former episode, and later aggressive action against the retreating Mexican army, earned him field promotion to the brevet rank of major.