Ralph Waldo Emerson - Poetry

Next up in the poetry list is the 'Concord Hymn' from Ralph Waldo Emerson, a name I recognize but I must admit I know next to nothing of the poet.  This poem is about the Battle of Concord, the first battle in the Revolutionary War.  It was first recited on July 4th, 1837.

By the rude bridge that arched the flood,
Their flag to April's breeze unfurled,
Here once the embattled farmers stood,
And fired the shot heard round the world.

The foe long since in silence slept;
Alike the conqueror silent sleeps;
And Time the ruined bridge has swept
Down the dark stream which seaward creeps.

On this green bank, by this soft stream,
We set today a votive stone;
That memory may their deed redeem,
When, like our sires, our sons are gone.

Spirit, that made those heroes dare
To die, or leave their children free,
Bid Time and Nature gently spare
The shaft we raise to them and thee.

You know what catches my eye after reading through this?  There is no mention of why the battle was fought.  This poem could apply to almost any battle that is fondly remembered.  Only the first stanza gives hints as to what happened.
Which may not be that big of a deal.  This poem debuted some sixty years after the fight took place and Emerson may have reasonably thought that the details would be well known to anyone that came to visit Concord.  Maybe it's a very modern thing that we feel the need to explain and justify our battles to future visitors.
The poetry is fine, though it doesn't really sing for me.  The line 'shot heard round the world' is famous and justly so.  I don't know that anything else here is striking.