O Tannenbaum
He is most remembered for writing the poem "Maryland, My Maryland," which is also the reason for his being called the "Poet Laureate of the Lost Cause". It became a war hymn of the Confederacy after the poem's words were set to the tune "Lauriger Horatius" (the tune of "O Tannenbaum") during the Civil War by Jennie Cary, a member of a prominent Maryland and Virginia family. It later became the state song of Maryland.