Technique
Invocation
From Latin invocare: to call upon. A classical convention deriving from Homer; the Muse addressed changes from Greek (Calliope) to Milton's Holy Spirit.
Definition
An appeal to a Muse, deity, or inspiring power at the beginning of an epic or long poem, requesting divine inspiration.
Example
Milton's Paradise Lost: 'Sing, Heav'nly Muse, that on the secret top / Of Oreb, or of Sinai, didst inspire…'