[4] Somewhere between 1856 and 1859 the Doyles moved to Richmond, Virginia, where Peter Sr. found employment at the Tredegar Iron Works.

[5] When the American Civil War broke out, Doyle enlisted in the Confederate States Army on April 25, 1861.

[5] He fought in several engagements of the war, including the Battle of Antietam, where he was wounded and he was discharged on November 7, 1862.

[15] The historian Martin G Murray wrote that Doyle may have influenced Whitman's famous poem "O Captain!

Doyle gradually grew unhappy with his job and continued to visit Whitman, even after he moved to Camden, New Jersey, in 1874.

[21] Doyle met Richard Maurice Bucke, a promoter and early biographer of Whitman, in 1880.

[22] After 1885, he moved permanently to Philadelphia,[23] where he was a member of the Benevolent and Protective Order of Elks and joined the United Confederate Veterans.

[6] For the rest of his life, Doyle was considered a celebrity by "friends and followers" of Whitman.

[27] He is buried in the Congressional Cemetery in Washington, D.C.[10] A portrait of Doyle and Whitman was taken around 1865 by M. P. Rice.

[28] Paraphrasing Thomas Gray's "Elegy Written in a Country Churchyard", John Burroughs described Doyle as "a mute inglorious Whitman".