President Lincoln's private secretary, John Nicolay recalled;
On August 22, 1862 President Lincoln wrote an open letter to Horace Greeley, editor of New York Tribune. This letter, which has become famous in history, he sent to the National Intelligencer for publication.
Dr. James Clarke Welling was at that time the editor in charge, and he did what few young editors would have ventured upon. He wanted to make a change to Lincoln’s text so he immediately carried the manuscript back to the President, and suggested its omission. President Lincoln good-naturedly complied, not that he was convinced of the alleged imperfection, but because he never stubbornly resisted advice where only trifles were concerned.
Recollections of John Nicolay
Private Secretary to President Lincoln
Princeton College Bulletin
Volume VII; April, 1895
From an early age, James Clarke Welling was passionate about historical accuracy. His college thesis at Princeton was Causes of Historical Discrepancies.Volume VII; April, 1895
In 1880 Welling made another revision to the Lincoln-Greeley letter, Aug. 22, 1862. He referred to the original letter in his possession and corrected the misprinted word from "this" union to "the" union.