Probably the most well-known poem by Walt Whitman, "O Captain! My Captain!" is a moving metaphor for President Abraham Lincoln's leadership of the country during the Civil War and his assassination which shocked the nation. This poem is actually only one of a handful that Whitman wrote in honor of Lincoln, whom he greatly admired. "O Captain" was written in 1865 shortly after the death of the President and was published later the same year in a small booklet containing a collection of 18 of Whitman's poems.

Complete notes: https://verses.porchlightfamilymedia.com/2018/04/o-captain-my-captain-by-walt-whitman.html