What battle did President Lincoln issued his Emancipation Proclamation?

Answer:
It was after the rather lucky Union win at Antietam (Sharpsburg) in September 1862, which gave Lincoln the chance to issue the Proclamation without making it sound like a desperate measure.
First answer by Jonathan Begg. Last edit by Jonathan Begg. Contributor trust: 151 [recommend contributor recommended]. Question popularity: 2 [recommend question].