simply an application of
common sense to the problem in hand.

Frequently two pieces of external evidence will accomplish what neither
one could do alone. Often one fact will show that a play came
somewhere before a certain date, but not show how long before, and
another will prove that the play came after another date, without
telling how long after. For example, _King Lear_ was written before
1606, for we have a definite statement that it was performed then. It
was written after 1603, for it borrowed material from a book printed in
that year. This method of hemming in a play between its earliest and
its latest possible date is common and useful, both with Shakespeare
and with other writers.

+Internal Evidence+.--By the above methods a few plays have been dated
quite accurately, and many others confined between limits only two or
three years {78} apart. But many plays are still dated very vaguely,
and some are not dated at all. For further results we must fall back
on internal evidence. The first, though by no means the most
important, form of this consists of allusions _within the play to
contemporary events_. If a boy should read in an old diary of his
grandmother's that she had just heard of the fight at Gettysburg, he
would feel certain that the words were written a few days after that
great battle, even if there were no date anywhere in the manuscript.
In the same way, when the Prologue of Shakespeare's _Henry V_ alludes
to the fact that Elizabeth's general (the Earl of Essex) is in Ireland
quelling a rebellion, we know that this was written between April and
September of 1599, the period during which Essex actually was in
Ireland. Similarly, certain details in _The Tempest_ appear to have
been borrowed from accounts of the wreck of Sir George Somers's ship in
1609. As Shakespeare could not have borrowed from these accounts
before they existed, he must have written his comedy sometime after
1609.[3]

But the main form of internal evidence, what is usually meant by that
term, is the testimony in the character and style of the plays
themselves as to the maturity of the man who wrote them. Just as the
stump of a tree sawn across shows its age by its successive rings of
growth, so a poem, if carefully {79} examined, shows the rings of
growth in the author's style of thought and expression.

The simplest and most tangible form of this evidence is that which is
found in meter. If we read in order of c