written by Longfellow after he'd lost his entire family (wife included) during the Civil War:
Someone seems to have embellished the tale a bit. Longfellow did not lose his entire faimly in the Civil War. The poem was written after his eldest son Charles was wounded, not killed, in battle; he wouldn't die until 1893, eleven years after his father. His wife was burned to death in a household accident in 1861. He wrote a different poem about that death, "The Cross of Snow", eighteen years later.