The five-stress or decasyllabic verse (iambic pentameter) is so much
more widely used in modern English poetry than any other verse-form,
that its history is of special interest. It is curious that a form so
completely adopted as the favorite of English verse should be borrowed
rather than native; but, the syllable-counting principle once being
admitted, there is nothing in five-stress verse inconsistent with native
English tendencies. A very great part of such verse has really only four
full accents, and this we have seen to be the number of accents in the
native English verse. On this point, see further remarks in connection
with the specimen from Spenser, p. 180 below.
This verse appears in two great divisions, rimed (the decasyllabic
couplet) and unrimed (blank verse). The rimed form was the earlier, the
unrimed being merely a modification of it under the influence of other
unrimed metres.