There was a requirement at the time for contractors to stamp their name and where the rations came from onto the food they were sending. Wilson's packages were labeled "E.A.—U.S." When someone asked what that stood for, a co-worker jokingly said, "Elbert Anderson [the contractor] and Uncle Sam," referring to Wilson, though the U.S. actually stood for "United States".[10] Doubts have been raised as to the authenticity of this story, as the claim did not appear in print until 1842.[11] Additionally, the earliest known mention definitely referring to the metaphorical Uncle Sam is from 1810, predating Wilson's contract with the government.[3] As early as 1835, Brother Jonathan made a reference to Uncle Sam, implying that they symbolized different things: Brother Jonathan was the country itself, while Uncle Sam was the government and its power.[12]