Ernest Thayer's Casey at the Bat was first published in the San Francisco Daily Examiner on June 3, 1888. Its popularity owed much to the universality of its subject; every city seemed to have a Casey on its team. Thayer, a Harvard graduate, said little about the real Casey, though he did leave a few clues. The verses owe their existence, he wrote in 1930, to my enthusiasm for college baseball...and to my association with Will Hearst. Thayer's background is examined here as the basis for determining the origins of the colorfast cast of characters behind his Ballad of the Republic--men who may have been Casey, Flynn, Cooney and other members of the Mudville Nine.