Horatius Coclès is an opera in one act and nine scenes (styled an acte lyrique) by the French composer Étienne Nicolas Méhul with a libretto by Antoine-Vincent Arnault.
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.
Populonia features in Horatius, the celebrated poem by Lord Macaulay - 'From seagirt Populonia,/Whose sentinels descry/Sardinia's snowy mountain-tops/Fringing the southern sky'.