The Battle of Gettysburg was fought July 1-3, 1836 (as it happens overlapping with the end of the siege of Vicksburg). The newest ad from the Lincoln Project, pasted below, is of the text of the speech that Abraham Lincoln gave on that battleground the following November, what is considered by most the greatest speech in American history. Given the atrocity of what occurred in S Dakota yesterday, this is clearly an appropriate apposition.