In Hamlet, what is the fate of Rosencrantz and Guildenstem?

Ronsencrantz and Guildenstern (R & G) are somewhat
mysterious figures in the play, as they are definitely old friends of Hamlet, but they
are also definitely sent for by King Claudius to work for him to find out whether Hamlet
is attempting to usurp the throne.  In the play, Claudius only mentions, upon their
arrival in Act II, scene ii, the following:

The
need we have to use you did provoke
Our hasty sending.. . .I do entreat you
both
That being of so young days brought up with [Hamlet],
That you
vouchsafe your rest here in our court,
. . .To draw him on to pleasures and to
gather
. . .Whether aught to us unknown afflicts him. .
.

The King is good at veiled language, but, as the
events of the play progress, R & G are revealed to the audience and Hamlet as
sort of hired thugs meant to assist Claudius in getting rid of Hamlet.  This is most
evidenced in Act IV scenes ii and iii.  And Claudius pronounces at the end of IV, iii
that he intends to send Hamlet to England and to his
death:

And
England, if my love thou hold'st at aught,

. . .thou mayst
no coldy set

Our sovereign process, which imports at
full,

By letters congruing to that
effect

The present death of
Hamlet.

So, R & G are
meant to be in conveyors of Hamlet to his death in England.  However, Hamlet outsmarts
them.  Upon his return to Denmark in Act V, he relays to Horatio that he switched a
letter condemning R & G to death with the one that they carried from the King
condemning him.  In this way, the King of England put R & G to death in place of
Hamlet.

For the quote from Act V relating this switch and
more on Rosencrantz and Guildenstern, please follow the links
below.