Almost from the moment the fire broke out, various theories about its cause began to circulate. The most popular and enduring legend maintains that the fire began in the O'Leary barn as Mrs. O’Leary was milking her cow. The cow kicked over a lantern (or an oil lamp in some versions), setting fire to the barn. The O'Leary family denied this, stating that they were in bed before the fire started, but stories of the cow began to spread across the city. Catherine O'Leary seemed the perfect scapegoat: she was a poor, Irish Catholic immigrant. During the latter half of the 19th century, anti-Irish sentiment was strong throughout the United States and in Chicago. This was intensified as a result of the growing political power of the city's Irish population. Furthermore, the United States had been distrustful of Catholics (or papists, as they were often called) since its beginning, carrying over attitudes in England in the 17th century; as an Irish Catholic, Mrs. O'Leary was a target of both anti-Catholic and anti-Irish sentiment. This story was circulating in Chicago even before the flames had died out, and it was noted in the "Chicago Tribune"'s first post-fire issue. In 1893 the reporter Michael Ahern retracted the "cow-and-lantern" story, admitting it was fabricated, but even his confession was unable to put the legend to rest. Although the O'Learys were never officially charged with starting the fire, the story became so engrained in local lore that Chicago's city council officially exonerated them—and the cow—in 1997.