Shiloh was one of the great battles of the American Civil War.
Confederate forces had encamped behind Shiloh Church near Pittsburgh in preparation for a final offensive against Union territory which they hoped might restore the balance of the conflict in their favour, when they were attacked by the Union army under Ulysses S Grant.
Both sides claimed victory, but on the following day the Union army attacked again and public opinion decided that overall they had won. Melville's poem is largely about the evening between.
It was written sometime later when he was already the author of Moby Dick which had been acclaimed by the critics but ignored by readers.
At about this time he was writing several poems of disillusion with the Civil War, reflecting his own feelings of disappointment at the fate of his great book.
As an author he was more or less forgotten by then but fortunately had found work as a Customs Officer in New York.
Skimming lightly, wheeling still,
The swallows fly low
Over the field in clouded days,
The forest-field of Shiloh -
Over the field where April rain
Solaced the parched one stretched in pain
Through the pause of night
That followed the Sunday fight
Around the church of Shiloh -
The church so lone, the log-built one,
That echoed to many a parting groan
And natural prayer
Of dying foemen mingled there -
Foemen at morn, but friends at eve -
Fame or country least their care:
(What like a bullet can undeceive!)
But now they lie low,
While over them the swallows skim
And all is hushed at Shiloh.