Whittier

Born on this day in 1807 was the Quaker poet and abolitionist John Greenleaf Whittier - hugely popular in his day (though the critics weren't uniformly kind) and today all but forgotten, except as the writer of the beautiful hymn Dear Lord and Father of Mankind. This was not written as a hymn, but is taken from a much longer poem, The Brewing of Soma, about the dangerous practices of Vedic priests. What's more, Hubert Parry's great melody Repton, to which the hymn is sung in Britain - and which fits it so perfectly - was not written for Whittier's words but as an aria in his oratorio Judith. It was adapted to Whittier's verse by the director of music at Repton - hence the name.
  For myself, I also remember Whittier for the stirring narrative poem Barbara Frietchie, a favourite of my father's and a regular feature of his impromptu morning recitations. I even remember fragments of it:

'Up from the meadows rich with corn,
Clear in the cool September morn,
The clustered spires of Frederick stand,
Green-walled by the hills of Maryland.'

Into this Edenic scene rides Stonewall Jackson's cavalry...

'Up rose old Barbara Frietchie then,
Bowed with her four score years and ten'

and defiantly she raises the Union flag in her attic window.

'"Halt!" - the dust-brown ranks stood fast.
"Fire!" - out blazed the rifle-blast.'

But Barbara Frietchie isn't done yet.

'"Shoot, if you must, this old gray head,
But spare your country's flag," she said.'

Jackson is shamed, his conscience stirred.

'"Who touches a hair of yon gray head
Dies like a dog! March on!" he said.'

How's that for caesura? You can read the whole poem here...