The "Battle Hymn of the Republic" (also known as "Mine Eyes Have Seen the Glory") is a hymn and American patriotic song, with lyrics written by Julia Ward Howe (1819–1910). She adapted the lyrics and melody from the folk song "John Brown's Body" which in turn was based on an older hymn called "Say, Brothers will you meet us". The verse and the chorus use essentially the same melody even though the former has more syllables.
Piano sheet music, plus midi and mp3 files for this hymn can be downloaded using the links in the left-hand menu or see below.
Here is a video of Battle Hymn of the Republic:
The image below is the first page of the sheet music, and here you can download the full sheet music for Battle Hymn of the Republic in PDF format.