What is a ballad?
A ballad is a traditional verse form. Ballads performed to music and passed down in the oral and folk tradition; thus ballads are usually anonymous. 19th century scholars were concerned that with the growth of literacy (and, at the end of the century, of mechanical reproduction of music) folk traditions were gradually disappearing. Thus they made major efforts to collect and preserve ballads by transcription or recording. Many modern writers imitate traditional ballad forms.
The ballad consists of quatrains rhymed abcb. The metrical scheme consists of alternating lines of iambic tetrameter and iambic trimeter. A typical example is Sir Patrick Spens:
"Laie late yestreen I saw the new moone,
Wi the auld moone in her arme,
And I feir, I feir, my deir master,
That we will cum to harme."