The meter of this poem, known as common meter or ballad meter, was actually very frequently used in ballads, hymns, and poetry of the Romantic and Victorian periods. Contra the second paragraph above, the lines do not consist of three or four "syllables", but rather alternate between iambic tetrameter and iambic trimeter (the latter often with feminine endings), and thus consist of four or three feet. An iambic foot consists of an unstressed followed by a stressed syllable. Thus a line of iambic tetrameter containing four feet contains a total of eight syllables and a line of iambic trimeter contains six syllables.