It was written by Abraham Lincoln to Lydia Bixby, who had lost two sons in the Civil War, with a third taken prisoner, a fourth missing as a deserter, and a fifth discharged from the army, his fate unknown. And its eloquence has gone down in history as evidence of Honest Abe’s deep humanity. “I feel how weak and fruitless must be any word of mine which should attempt to beguile you from the grief of a loss so overwhelming,” he wrote. “But I cannot refrain from tendering you the consolation that may be found in the thanks of the republic they died to save.” The text of the letter is well-known, but the original went missing. Its sentiment—that no mother should have to lose more than one son—was the basis of Steven Spielberg’s Saving Private Ryan. Now the Dallas Historical Society thinks it has found the real thing buried in a file. Is the letter genuine or a forgery? Forensic testing will soon provide the answer.