On May 7, 1858, after winning the acquittal of William Duff Armstrong in the celebrated Almanac Trial at the Cass County Courthouse in Beardstown, Abraham Lincoln was persuaded by the young entrepreneur Abraham Byers to walk to Byers' nearby studio for a brief photography session. According to some accounts, Lincoln at first declined because his suit was too rumpled, but Byers convinced him to pose. Using the ambrotype process, which imaged a negative on glass backed by a dark surface, Byers took two photographs. One was lost or, by some accounts, discarded, and the other showed a tired Lincoln in a white linen suit, seated with his right arm resting on a chair. The seven-by-nine-inch ambrotype, mounted in an ornate brass frame, is the only known portrait of Lincoln in a white suit and is generally believed to be one of ten photographs taken of him during 1858. A copy hangs in the courtroom where Lincoln defended Armstrong. Owned by the University of Nebraska, the photograph is usually kept in a vault, though it was displayed at the National Portrait Gallery in Washington, D.C., during the bicentennial celebration in 1976. Byers, who taught himself ambrotype photography after gaining the studio in settlement of an unpaid loan, was a store clerk who also spent much time in Nebraska in land speculation. According to his daughter, Olive Byers Hayes, he developed a friendship with Lincoln in the 1850s. He married Mary Tull in Beardstown in 1861, later moved to Aledo, Illinois, and became a successful banker. After Mary's death in 1902, he remarried, eventually went to Omaha, and died there in 1920. His widow, Zora, donated the photograph to the University of Nebraska.