But the Duchess's new reign of conquest was destined to be brief. To the
consternation of her Royal lover she was struck down with small-pox,

"by which," to quote Pepys again, "all do conclude she
will be wholly spoiled, which is the greatest instance of
the uncertainty of beauty that could be in this age; but
then she hath had the benefit of it to be first married,
and to have kept it so long, under the greatest
temptations in the world from a King, and yet without the
least imputation."

That Pepys's fears were realised we know from Ruvigny's letters to Louis
XIV., in which he says that "her matchless beauty was impaired beyond
recognition, one of her brilliant eyes being nearly quenched for ever."
During this tragic illness Charles, who was consumed with anxiety,
visited her more than once, thus proving, at a terrible risk, the
sincerity of his devotion. And it is even said that his admiration of
her was not diminished by the loss of her beauty.

With this loss of her beauty, however, the Duchess's reign may be said
to have come to an end. King Charles's eyes were soon to be dazzled by
the fresher charms of Louise de Querouaille, whom the "Sun-King" had
sent from France to turn his head and influence his foreign policy in
Louis's favour; and _La belle Stuart_ was not slow to realise that at
last her sun had set. During the remainder of her long life, at least
until the Orange King came to the Throne, she retained her office of
Lady of the Bedchamber to two Queens; but her appearances at Court, the
scene of so many triumphs, were as few as she could make them.

For the rest her days were spent in retirement, among her beloved books