www.alphadictionary.com

1. A conflict, especially between the protagonist and antagonist in a work of literature.

2. The part of an ancient Greek drama, especially a comedy, in which two characters engage in verbal dispute.

3. A test of will; a conflict: "Freud's originality stemmed from his aggression and ambition in his agon with biology"

4. A contest in ancient Greece, as in athletics or music, in which prizes were awarded.

Also, as you might imagine, related to agony. I like the death throes meaning of this one.

History repeats itself agon and agon.

History repeats itself agon and agon.

Reminds me of an old, old song:

A long, long time agon...
I can still remember
How that music used to make me smile.