Following the Battle of Gettysburg on July 1–3, 1863, the removal of the fallen Union soldiers from the Gettysburg Battlefield graves and their reburial in graves at the National Cemetery at Gettysburg began on October 17. In inviting President Lincoln to the ceremonies, David Wills, of the committee for the November 19 Consecration of the National Cemetery at Gettysburg, wrote, "It is the desire that, after the Oration, you, as Chief Executive of the nation, formally set apart these grounds to their sacred use by a few appropriate remarks."
On the train trip from Washington, D.C., to Gettysburg on November 18, Lincoln was accompanied by three members of his Cabinet, William Seward, John Usher and Montgomery Blair, several foreign officials, his secretary John Nicolay, and his assistant secretary, John Hay. During the trip Lincoln remarked to Hay that he felt weak; on the morning of November 19, Lincoln mentioned to Nicolay that he was dizzy. Hay noted that during the speech Lincoln's face had "a ghastly color" and that he was "sad, mournful, almost haggard." After the speech, when Lincoln boarded the 6:30 pm train for Washington, D.C., he was feverish and weak, with a severe headache. A protracted illness followed, which included a vesicular rash; it was diagnosed as a mild case of smallpox. It thus seems highly likely that Lincoln was in the prodromal period of smallpox when he delivered the Gettysburg address.